The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our condensed consolidated financial statements and related notes and other financial information included elsewhere in this Quarterly Report on Form 10-Q and our audited consolidated financial statements and notes thereto for the year ended December 31, 2025 filed with the Securities and Exchange Commission (“SEC”) on February 24, 2026. This discussion and analysis contain forward-looking statements based upon our current beliefs, plans and expectations that involve risks, uncertainties and assumptions, such as statements regarding our plans, objectives, expectations, intentions and beliefs. Our actual results and the timing of events could differ materially from those anticipated in these forward-looking statements as a result of various factors, including those set forth under the section titled “Risk Factors” and elsewhere in this Quarterly Report on Form 10-Q. You should carefully read the “Risk Factors” section of this Quarterly Report on Form 10-Q to gain an understanding of the important factors that could cause actual results to differ materially from our forward-looking statements. Please also see the section titled “Special Note Regarding Forward-Looking Statements.” Overview We are a clinical-stage vaccine innovation company engineering high-fidelity vaccines to protect humankind from the consequences of bacterial diseases. We are re-engineering the way highly complex vaccines are made through the XpressCF™ cell-free protein synthesis platform. Unlike conventional cell-based approaches, our system for producing difficult-to-make proteins and antigens is intended to develop and deliver high-fidelity vaccines with enhanced immunological benefits that are beyond the capabilities of conventional approaches. Our pipeline includes: •PCV candidates that we believe are among the broadest-spectrum PCV candidates currently in development, targeting the approximately $8 billion global pneumococcal vaccine market. Pneumococcal disease ("PD") is an infection caused by Streptococcus pneumoniae bacteria. It can result in invasive pneumococcal disease (“IPD”), including meningitis and bacteremia, and non-invasive PD, including pneumonia, otitis media and sinusitis. Our broad-spectrum, carrier-sparing PCV candidates, VAX-31, VAX-24 and VAX-XL, are designed to improve upon standard-of-care PCVs for both adults and children by covering the serotypes that are responsible for increasing portions of IPD in circulation and are associated with high case-fatality rates, antibiotic resistance and meningitis, while maintaining coverage of previously circulating strains that are currently contained through continued vaccination. ◦PCV Franchise Adult Indication: ▪VAX-31 is a 31-valent, broad-spectrum, carrier-sparing investigational PCV being developed for the prevention of IPD and pneumonia. VAX-31 is the broadest-spectrum PCV in the clinic, and has the potential to provide protection against both currently circulating and historically prevalent serotypes. VAX-31 was designed to increase coverage, in a single vaccine, to approximately 95% of IPD and approximately 88% of pneumococcal pneumonia circulating in adults in the United States aged 50 and older, with the potential to provide an incremental 13-36% broader coverage for IPD and an incremental 19-31% broader coverage for pneumococcal pneumonia over current standard-of-care adult PCVs. •In September 2024, we announced positive topline results from a Phase 1/2 study of VAX-31 in adults. The VAX-31 Phase 1/2 clinical study was a randomized, observer-blind, active-controlled, dose-finding clinical study designed to evaluate the safety, tolerability and immunogenicity of a single injection of VAX-31 at three dose levels (Low, Middle and High) and compared to Prevnar 20® ("PCV20") in 1,015 healthy adults aged 50 and older. In the Low, Middle and High Doses, all serotypes were dosed at 1.1mcg, 2.2mcg and 3.3mcg, respectively, except serotypes 1, 5 and 22F, which were dosed at 1.65mcg, 3.3mcg, and 4.4mcg, respectively. The Phase 1 portion of the study included 64 healthy adults 50 to 64 years of age and the Phase 2 portion included 951 healthy adults 50 years of age and older. The immunogenicity objectives of the study included an assessment of the induction of antibody responses at Month 1, based on opsonophagocytic activity (“OPA”) and immunoglobulin G ("IgG"), at each of the 21 Table of Contents three VAX-31 doses and compared to PCV20 for the 20 serotypes in common, as well as for the additional 11 serotypes contained in VAX-31, but not in PCV20. In the Phase 1/2 study, VAX-31 was observed to be well tolerated and demonstrated a safety profile at all doses studied through the full six-month evaluation period similar to PCV20. VAX-31 showed robust OPA immune responses for all 31 serotypes at all doses studied. At the Middle and High Doses, VAX-31 met or exceeded the regulatory immunogenicity criteria for all 31 serotypes and, at the Low Dose, for 29 of 31 serotypes. At the VAX-31 High Dose, average OPA immune responses were greater for 18 of 20 serotypes compared to PCV20 (geometric mean ratio (“GMR”) greater than 1.0), with seven of these serotypes achieving statistically higher immune responses compared to PCV20. At the Middle Dose, 13 of 20 serotypes had a GMR greater than 1.0 and five serotypes achieved statistically higher immune responses compared to PCV20. At the Low Dose, 18 of 20 serotypes met the OPA response non-inferiority criteria, 8 of 20 serotypes had a GMR greater than 1.0 and three serotypes achieved statistically higher immune responses. For all 11 incremental serotypes unique to VAX-31, and not in PCV20, all three doses met the superiority criteria. Based on these positive results, we selected the High Dose of VAX-31 to advance to an adult Phase 3 program. •In November 2024, we announced that the U.S. Food and Drug Administration ("FDA") granted breakthrough therapy designation ("BTD") for VAX-31 for the prevention of IPD in adults and, in August 2025, we announced that the FDA expanded the BTD for VAX-31 to include the prevention of pneumonia caused by Streptococcus pneumoniae. •In December 2025, following an FDA End-of-Phase 2 meeting, we announced that the first participants were dosed in a Phase 3 pivotal, non-inferiority trial ("OPUS-1") evaluating the safety, tolerability and immune responses of VAX-31 in healthy, pneumococcal-naïve (defined as having no known prior history of IPD or pneumococcal pneumonia, or receipt of any licensed or investigational pneumococcal vaccine) adults aged 50 and older through direct, head-to-head comparisons with both PVC20 and PCV21, the current standard-of-care PCVs. In March 2026, we announced that we completed enrollment of this trial. We expect to announce topline safety, tolerability and immunogenicity data from this study in the fourth quarter of 2026. •In January 2026, we announced the initiation of an additional Phase 3 trial evaluating VAX-31 when administered concomitantly with a licensed, high-dose seasonal influenza vaccine in pneumococcal-naïve adults aged 50 years and older (“OPUS-2”). In February 2026, we announced the initiation of a separate Phase 3 study evaluating VAX-31 in adults previously vaccinated with a lower-valency pneumococcal vaccine (“OPUS-3”). In March 2026, we announced we completed enrollment of the OPUS-2 trial and in May 2026, we announced we completed enrollment of the OPUS-3 trial. We expect to report safety, tolerability and immunogenicity data from the OPUS-2 and OPUS-3 studies in the first half of 2027. We are also planning for a manufacturing consistency study (e.g., a lot-to-lot study) as the final Phase 3 study to enable the submission of the Biologics License Application (BLA). ◦PCV Franchise Pediatric Indication: ▪VAX-31 is a 31-valent, broad-spectrum, carrier-sparing investigational PCV also being developed for the prevention of IPD in children. VAX-31 is the broadest-spectrum PCV in the clinic designed to cover approximately 91% of IPD in U.S. children under five years of age and approximately 96% of otitis media due to Streptococcus pneumoniae in U.S. children five years of age or under. ▪In December 2024, we announced that the first participants were dosed in the first stage of a Phase 2, randomized, dose-finding study of VAX-31 in infants. Stage 1 of the study evaluated the safety and tolerability of VAX-31 at three dose levels (Low, Middle and High) and compared to PCV20 in 48 infants in a dose-escalation approach. In the Low, Middle and High Doses, all serotypes were dosed at 1.1mcg, 2.2mcg and 22 Table of Contents 3.3mcg, respectively, except serotypes 1, 5 and 22F, which were dosed at 1.65mcg, 3.3mcg, and 4.4mcg, respectively. Participants who received VAX-31 in Stage 1 continued the standard dosing regimen as part of Stage 2. ▪In February 2025, we announced that the Phase 2, randomized, dose-finding study of VAX-31 in healthy infants had advanced to the second stage of the study. Stage 2 of the study is evaluating the safety, tolerability and immunogenicity of VAX-31 at the same three dose levels evaluated in Stage 1 and compared to PCV20. In line with recommendations from the ACIP, the study design includes a primary immunization series consisting of three doses given at two months, four months and six months of age, followed by a subsequent booster dose at 12-15 months of age. ▪In September 2025, we announced advancement of the VAX-31 infant Phase 2 randomized, dose-finding study to the third and final stage following modifications to the protocol to add a new dose arm to evaluate a VAX-31 Optimized Dose (majority of serotypes dosed at 4.4mcg and the balance dosed at 3.3mcg) and discontinue further enrollment in the Low Dose arm. The Middle and High Dose arms continued as planned. ▪The modified study is evaluating the safety, tolerability and immunogenicity of VAX-31 and compared to PCV20 in 900 participants, including the 100 participants previously enrolled in the Low Dose arm. ▪In January 2026, we announced that we completed enrollment of this study. We expect to announce topline safety, tolerability and immunogenicity data from the primary three-dose immunization series and booster dose either sequentially or together by the end of the first half of 2027. ▪Pending the VAX-31 Phase 2 infant study readout, we plan to initiate a Phase 3 program in infants with an Optimized Dose formulation of VAX-24 or VAX-31. ▪VAX-24 is a 24-valent, broad-spectrum, carrier-sparing investigational PCV being developed for the prevention of IPD in infants, and it covers more serotypes than any pneumococcal infant vaccine on the market today. •In March 2025, we announced positive topline, interim data from the VAX-24 infant Phase 2 study, a randomized, observer-blind, dose-finding two-stage clinical study evaluating the safety, tolerability and immunogenicity of VAX-24 in healthy infants that enrolled 803 participants. •In November 2025, we announced final safety, tolerability, and immunogenicity results from the VAX-24 infant Phase 2 study that were consistent with the positive interim data reported in March 2025 and showed that VAX-24 elicited robust, dose-dependent immune responses, with little to no evidence of carrier suppression observed. The final data analysis included full 6-month safety results and complete post-dose 3 (primary immunization series) and post-dose 4 (booster dose) IgG and OPA results. The key immunogenicity endpoints included an assessment of immune responses for each of the VAX-24 dose levels (Low, Mid, Mixed) compared to PCV20 for the 20 common and 4 unique serotypes in VAX-24. At 1-month post-dose 3 and post-dose 4, immune responses were assessed based on serotype-specific IgG seroconversion rates (IgG threshold value of ≥0.35mcg/mL). IgG GMRs were also assessed at 1-month post-dose 3 and post-dose 4, along with other key immunogenicity endpoints, including OPA. In this study, VAX-24 was well-tolerated and demonstrated a safety profile similar to PCV20 across all doses studied. Post-dose 3 and post-dose 4, all VAX-24 doses evaluated demonstrated robust IgG and OPA immunogenicity responses. •Post-dose 3, all VAX-24 doses met target precedent Phase 2 non-inferiority criteria on relative seroconversion rates (lower limit of the 95% confidence interval for the difference between the proportion of participants achieving the pre-defined seroconversion rate (IgG concentration ≥0.35 mcg/mL) is > -15% for each serotype) for the highest circulating serotypes, as defined by the 23 Table of Contents percentage of IPD caused in individuals <5 yrs of age in the U.S. in 2023 based on the U.S. Center for Disease Control ("CDC") active bacterial core ("ABC") surveillance data, contained in VAX-24. The Low and Mid doses met the seroconversion rate criteria for 20 of 24 serotypes overall and the Mixed Dose met such criteria for 19 of 24 serotypes. The Mid and Mixed Doses met the target Phase 2 IgG GMR point estimate of >0.6 for 21 of 24 serotypes. •Post-dose 4, all VAX-24 doses met our target Phase 2 IgG GMR point estimate of >0.6 for the three highest circulating serotypes contained in VAX-24. The Mixed Dose met this target for 19 of 24 serotypes overall and the Mid dose met this target for 18 of 24 serotypes. Post-dose 4, VAX-24 elicited robust memory responses across all doses for all serotypes. •Additionally, the four incremental serotypes unique to VAX-24 that provide expanded serotype coverage relative to PCV20 elicited robust immune responses and met all target criteria across all endpoints at all doses evaluated. •The final data from the VAX-24 infant Phase 2 dose-finding study further supported our rationale for exploring higher doses in the ongoing VAX-31 infant Phase 2 study. ◦VAX-XL is a third-generation PCV candidate designed to provide the broadest coverage of any PCV currently in development. •VAX-A1, a novel conjugate vaccine candidate designed to prevent disease caused by Group A Streptococcus (Streptococcus pyogenes) (“Group A Strep”). Group A Strep is pervasive globally and causes an estimated 800 million cases of illness annually, including pharyngitis, or strep throat, and certain severe invasive infections and sequelae. There is currently no vaccine against Group A Strep, which is one of the leading infectious disease-related causes of death and disability worldwide and a significant contributor to the prescription of antibiotics in children. We believe we have demonstrated preclinical proof of concept for VAX-A1, the data for which were published in December 2020. In June 2026, we initiated a Phase 1 adult study for VAX-A1, with the primary objective of assessing safety and tolerability, along with a secondary objective of evaluating initial immunogenicity data, to support potential further advancement. We expect to report topline data from this study in the second half of 2027. •VAX-GI, a novel preclinical vaccine candidate being developed as a preventative treatment for dysentery and shigellosis, which is caused by Shigella bacteria. Shigella is a bacterial illness estimated to cause 80 million to 165 million cases of disease and 600,000 deaths annually, mostly among children. The central antigen in VAX-GI is IpaB, a well-appreciated antigen that other developers have been unable to produce in an amount sufficient to enable a commercial product. With our cell-free technology, we believe we can produce this antigen at substantially improved yields, allowing for commercial-scale production. VAX-GI is being developed in collaboration with the University of Maryland, Baltimore as well as with partial funding from two research grants awarded by the National Institutes of Health (“NIH”). As part of our continued focus on strategic capital deployment and in order to prioritize our resources towards our PCV franchise, we announced in August 2025 that we had paused the advancement, beyond preclinical development, of VAX-GI while remaining confident in its potential and preserving the option to advance the program in the future. •Other discovery-stage programs that leverage our cell-free protein synthesis platform, which, if proven successful in preclinical studies, could also be advanced into IND-enabling activities and clinical studies. Since March 31, 2026, key developments affecting our business include the following: •Advanced VAX-31 Adult Phase 3 Program: All three ongoing VAX-31 Phase 3 clinical trials (OPUS-1, OPUS-2 and OPUS-3) are now fully enrolled with 6,191 adults dosed in total, approximately 3,500 of whom received VAX-31. These studies, which were finalized in consultation and alignment with the FDA, are designed to generate a broad and robust safety, tolerability and immunogenicity dataset. In addition, we are planning a 24 Table of Contents manufacturing consistency study (e.g., a lot-to-lot study) as the final Phase 3 study to enable the submission of the BLA. •Initiated Phase 1 Study Evaluating VAX-A1, a Potential Best-in-Class Vaccine Candidate Designed to Provide Broad Protection Against Disease Caused by Group A Streptococcus: In June 2026, we announced that the first participant was dosed in the Phase 1, first-in-human study evaluating VAX-A1, an investigational prophylactic vaccine candidate designed to prevent disease caused by Group A Strep, with the primary objective of assessing safety and tolerability, along with a secondary objective of evaluating initial immunogenicity data, to support potential further advancement. All participants enrolled in Stage 1 of the study have received the first of two planned doses. The Stage 2 portion of the study is expected to proceed contingent upon the Data Safety Monitoring Board's approval following the review of unblinded Stage 1 safety and tolerability data. All participants in the study will be evaluated for safety through six months after receiving the second dose. Group A Strep remains a major global cause of morbidity and mortality in adults and children and is a leading driver of antibiotic use, underscoring the significant public health burden.' •Appointment and Retirement of Directors: The Board of Directors has appointed two new members, Dr. Moncef Slaoui and Dr. John Markels, to replace retiring members, Mr. Jacks Lee and Dr. Heath Lukatch. We thank both retiring members for their considerable contributions during their service. Dr. Slaoui most recently served as Chief Scientific Advisor of Operation Warp Speed, the U.S. government effort to accelerate the development of COVID-19 vaccines. Prior to that, Dr. Slaoui spent nearly 30 years at GlaxoSmithKline, where he served as a member of the board of directors of GSK plc; Chairman of Pharmaceutical R&D; Chairman of Global R&D, Vaccines and Oncology; and Chairman of Global Vaccines, during which he was directly involved in building the company's vaccine pipeline. Dr. John Markels brings over 35 years of leadership experience in the pharmaceutical industry, including a longstanding tenure with Merck where he most recently served as President of Merck Global Vaccines. He has worked across global commercial leadership, strategy and organizational development, as well as manufacturing, development and technology transfer. Since our inception in November 2013, we have devoted substantially all of our resources to performing research and development, undertaking preclinical studies, advancing our vaccine candidates through clinical trials, enabling manufacturing activities in support of our product development efforts, acquiring and developing our technology and vaccine candidates, organizing and staffing our company, performing business planning, establishing our intellectual property portfolio and raising capital to support and expand such activities. We do not have any products approved for sale and have not generated any revenue from product sales. To date, we have financed our operations primarily with proceeds from the sales of our common stock, pre-funded warrants to purchase our common stock and, prior to our initial public offering (“IPO”) in June 2020, redeemable convertible preferred stock. We will continue to require additional capital to develop and commercialize our vaccine candidates and fund operations for the foreseeable future. Accordingly, until such time as we can generate significant revenue from sales of our vaccine candidates, if ever, we expect to finance our cash needs through public or private equity or debt financings, third-party (including government) funding and marketing and distribution arrangements, as well as other collaborations, strategic alliances and licensing arrangements, or any combination of these approaches. We have incurred net losses in each year since inception and expect to continue to incur net losses in the foreseeable future. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending in large part on the timing of our clinical trials and manufacturing activities, and our expenditures on other research and development activities. Our net loss was $284.3 million and $604.9 million for the three and six months, respectively, ended June 30, 2026. As of June 30, 2026, we had an accumulated deficit of $2.8 billion and cash, cash equivalents and investments of $2.5 billion. We believe our cash, cash equivalents and investments will be sufficient to fund our operating expenses and capital expenditure requirements through at least 12 months from the filing date of this Quarterly Report on Form 10-Q. We do not expect to generate any revenue from commercial product sales unless and until we successfully complete development and obtain regulatory approval for one or more of our vaccine candidates, which we expect will take a number of years. We expect our expenses will increase in connection with our ongoing activities, as we: •advance our vaccine candidates through preclinical studies and clinical trials; •progress in the scale-up of our manufacturing capabilities, in particular to prepare for the potential commercial launches of VAX-31 in the adult population and VAX-31 or VAX-24 in the pediatric population; •incur additional costs that may be required for secondary supply sources; •require the manufacture of supplies for our clinical trials; •conduct clinical trials, in particular VAX-31 and VAX-24; 25 Table of Contents •pursue regulatory approval of our vaccine candidates; •establish additional manufacturing capacity to meet potential incremental supply requirements following the potential commercial launches of VAX-31 in the adult population and VAX-31 or VAX-24 in the pediatric population; •hire additional personnel; •scale medical affairs and commercial infrastructure to support anticipated product launches; •expand our facilities to support our growing workforce and lab activities; •acquire, discover, validate and develop additional vaccine candidates; and •obtain, maintain, expand and protect our intellectual property portfolio. We rely and will continue to rely on third parties to conduct our preclinical studies and clinical trials and for manufacturing and supply of our vaccine candidates. We have no internal manufacturing capabilities, and we will continue to rely on third parties, of which the main suppliers are single-source suppliers, for our preclinical and clinical trial materials. Given our stage of development, we do not yet have a marketing or sales organization and have a limited commercial infrastructure. Accordingly, if we obtain regulatory approval for any of our vaccine candidates, we also would expect to incur significant commercialization expenses related to product sales, marketing, manufacturing and distribution. Because of the numerous risks and uncertainties associated with vaccine development, we are unable to predict the timing or amount of increased expenses or when or if we will be able to achieve or maintain profitability. Even if we are able to generate revenue from the sale of our vaccines, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and may be forced to reduce our operations. Certain Significant Relationships Lonza Ltd. (“Lonza”) Development and Manufacturing Services Agreements In April 2022, we entered into a non-exclusive development and manufacturing services agreement with Lonza effective as of March 22, 2022, which was subsequently amended on May 12, 2022, November 21, 2022 and October 31, 2023 (as amended, the “2022 Lonza DMSA”). Pursuant to the 2022 Lonza DMSA, Lonza is obligated to perform services, including manufacturing process development and clinical manufacture and supply of our proprietary PCV candidates. Subject to the terms and conditions set forth in the 2022 Lonza DMSA, Lonza has granted to us a non-exclusive, worldwide, fully paid-up, irrevocable, transferable license, including the right to grant sublicenses, under the New General Application Intellectual Property, to research, develop, make, have made, use, sell and import the Product. Unless earlier terminated, the 2022 Lonza DMSA shall remain in place for a period of five years. Either party may terminate the 2022 Lonza DMSA for any reason on prior written notice to the other party, provided that Lonza may not exercise such right until a specified future date. In addition, either party may terminate the 2022 Lonza DMSA (i) within a given time period upon any material breach that is left uncured by the other party, or (ii) immediately if the other party becomes insolvent. We may also terminate the 2022 Lonza DMSA upon an extended force majeure event. Upon expiration and/or termination of the 2022 Lonza DMSA and/or any purchase order, we will pay Lonza for all service rendered, all costs incurred, all unreimbursed capital equipment and any cancellation fees (each term as defined in the 2022 Lonza DMSA). In February 2023, we entered into another non-exclusive development and manufacturing services agreement with Lonza effective as of March 1, 2023 (the “2023 Lonza DMSA”). Pursuant to the 2023 Lonza DMSA, Lonza will perform manufacturing process development and the manufacture of components for our PCV candidates, including the polysaccharide antigens, our proprietary eCRM protein carrier and conjugated drug substances. Subject to the terms and conditions set forth in the 2023 Lonza DMSA, Lonza has granted to us a non-exclusive, worldwide, fully paid-up, transferable license, including the right to grant sublicenses (subject to the prior written consent of Lonza), under the New General Application Intellectual Property, to use, sell and import the Product manufactured under the 2023 Lonza DMSA (but no other products). Unless earlier terminated, the 2023 Lonza DMSA shall remain in place for a period of five years and shall automatically renew for one additional two-year period unless either party provides written notice of non-renewal at least two years prior to the fifth anniversary of the effective date. We may terminate the 2023 Lonza DMSA for any reason on prior written notice to the other party on a Project Plan-by-Project Plan basis. Either party may terminate the 2023 Lonza DMSA (i) within a given time period upon any material breach that is left uncured by the other party, (ii) immediately if the other party becomes insolvent, is dissolved or liquidated, makes a general assignment for the benefit of 26 Table of Contents its creditors, or files or has filed against it, a petition in bankruptcy or has a receiver appointed for a substantial part of its assets, (iii) upon an extended force majeure event, or (iv) if it becomes apparent to either party at any stage in the provision of the Services that it will be impossible to complete the Services for scientific or technical reasons despite exercise of best commercial efforts by both parties. Pursuant to the reason for termination and the party initiating the termination, we will pay Lonza for some combination of services rendered, costs incurred, unreimbursed capital equipment and/or any cancellation fees. Upon an extended force majeure event, neither party shall have any further liability to the other party (each term as defined in the 2023 Lonza DMSA). Under each of the 2022 Lonza DMSA and 2023 Lonza DMSA (collectively, the “Lonza Agreements”), we pay Lonza agreed-upon fees for their performance of development and manufacturing services and pass-through expenses incurred by Lonza for raw materials, as well as customary procurement and handling fees. Under each Lonza Agreement, we own all rights, title and interest in and to any and all New Customer Intellectual Property (as defined in each Lonza Agreement), and Lonza owns all rights, title and interest in New General Application Intellectual Property (as defined in each Lonza Agreement). Commercial Manufacturing and Supply Agreement On October 13, 2023, we entered into a pre-commercial services and commercial manufacturing supply agreement with Lonza (the “Lonza Commercial Manufacturing and Supply Agreement”). Pursuant to the Lonza Commercial Manufacturing and Supply Agreement, Lonza constructed and built out a dedicated suite (the “Suite”) at Lonza’s facilities in Visp, Switzerland to manufacture certain key components (including drug substance) for our proprietary PCV franchise and any other products or intermediates we may choose (collectively, the “Products”). Following completion of construction and certification of the Suite for commercial operation, the Suite was handed over to the Lonza operations team on August 1, 2026, and Lonza will now maintain and operate the Suite (utilizing Lonza’s employees) to manufacture the Products as a service provided to us, including conducting related quality control and quality assurance operations. Lonza is a preferred, non-exclusive, supplier of the Products to us, and we retain the right to procure the Products from one or more alternate and/or backup manufacturers of the Products (including at our own facilities). Under the Lonza Commercial Manufacturing and Supply Agreement, prior to completion of construction and certification of the Suite for commercial operation, we contributed to the capital expenditure costs to construct the Suite (and own certain equipment in the Suite that was purchased or otherwise acquired by us), and paid Lonza a fixed-rate monthly service fee for Lonza’s pre-commercial services prior to commencement of commercial operations. We will now pay Lonza (i) Suite fees based on allocations of certain of Lonza’s costs to maintain the facility in which the Suite is located and to provide shared services to us and Lonza’s other customers in such facility, (ii) service fees based upon Lonza’s actual full-time equivalent employee (“FTE”) costs to operate the Suite to manufacture the Products, and (iii) equipment expenditures and certain other pass-through costs, including for raw materials. In addition, we may be obligated to pay or reimburse Lonza for certain other fees and expenses under the Lonza Commercial Manufacturing and Supply Agreement. Lonza will be eligible for certain financial bonuses, and subject to certain financial penalties, as incentives for the timely completion of certain scale-up activities, receipt of certain regulatory approvals for the Suite and manufacture of the Products in accordance with our commercial requirements. Unless earlier terminated, the Lonza Commercial Manufacturing and Supply Agreement will remain in effect until December 31, 2038, subject to automatic renewal for up to three additional renewal periods of five years each, unless we elect not to renew (with 24 months advanced notice to Lonza). We are permitted to terminate the Lonza Commercial Manufacturing and Supply Agreement prior to expiration, subject to applicable termination fees. Within 30 days of the Effective Date, we paid Lonza a repurposing fee (the “Repurposing Fee”) of CHF 27.0 million that will be credited back to us over a 10-year period starting upon commencement of commercial production. 2026 Development and Manufacturing Services Agreement In February 2026, we entered into a development and manufacturing services agreement with Lonza, effective as of January 1, 2026, pursuant to which Lonza will perform manufacturing process development and commercial manufacture and supply of certain key components for our proprietary PCV franchise. Under the agreement, we will pay Lonza for development and manufacturing services, in addition to paying for certain raw material and other costs. We will be required to purchase, and Lonza will be required to supply, the components pursuant to the relevant purchase orders under the agreement. In consideration of the commercial supply services and Lonza’s other obligations under the agreement, we will pay Lonza a daily fee for Lonza’s operation of the facility solely to actively manufacture the components. With respect to such commercial supply, and subject to termination rights, we and Lonza have agreed to a mutually binding percentage 27 Table of Contents of annual facility capacity that shall be utilized by Lonza fully and exclusively for Lonza’s performance of services thereunder, which percentages may be adjusted under certain circumstances. Unless earlier terminated, the agreement will remain in effect until December 31, 2038, subject to automatic renewal for up to three additional renewal periods of five years each, unless we elect not to renew. We may terminate the agreement for convenience, and the agreement contains customary for-cause termination rights for each party. If the Agreement is terminated (i) by us for convenience, or (ii) by Lonza for our uncured failure to pay material, undisputed amounts of money due to Lonza, then we shall pay Lonza certain cancellation fees as specified in the agreement. Sutro Biopharma Amended and Restated License Agreement We are party to an amended and restated license agreement with Sutro Biopharma, dated October 12, 2015, which was subsequently amended on May 9, 2018, May 29, 2018, September 28, 2023 and November 21, 2023 (as amended, the “Sutro Biopharma License Agreement”). Under the Sutro Biopharma License Agreement, we received an exclusive, worldwide, royalty-bearing, sublicensable license under Sutro Biopharma’s patents and know-how relating to cell-free expression of proteins to (i) research, develop, use, sell, offer for sale, export, import and otherwise exploit specified vaccine compositions, such rights being sublicensable, for the treatment or prophylaxis of infectious diseases, excluding cancer vaccines, and (ii) manufacture, or have manufactured by an approved contract manufacturing organization, such vaccine compositions from extracts supplied by Sutro Biopharma pursuant to the Sutro Biopharma Supply Agreement (as described below). We are obligated to use commercially reasonable efforts to develop, obtain regulatory approval for and commercialize the vaccine compositions. In consideration of the rights granted under the Sutro Biopharma License Agreement, we are obligated to pay Sutro Biopharma a 4% royalty on worldwide aggregate annual net sales of our vaccine products for human health and a 2% royalty on such net sales of vaccine products for animal health. Such royalty rates are subject to specified reductions, including standard reductions for third-party payments and for expiration of relevant patent claims. We are also obligated to pay Sutro Biopharma any royalties due to Stanford University (the upstream licensor of Sutro Biopharma), to the extent the royalties payable by Sutro Biopharma to Stanford University are greater than the royalties payable by us to Sutro Biopharma. Royalties are payable on a vaccine composition-by-vaccine composition and country-by-country basis until the later of expiration of the last valid claim in the licensed patents covering such vaccine composition in such country and 10 years after the first commercial sale of such vaccine composition. The latest expiration date of a licensed Sutro Biopharma patent application, if issued, would be 2036, subject to any adjustment or extension of patent term that may be available in a particular country. In addition, we are obligated to pay Sutro Biopharma a percentage of net sublicensing revenue received in the low teen percentages. In addition, in the event we sublicense our non-manufacturing rights under the Sutro Biopharma License Agreement before a specified date, we are obligated to pay Sutro Biopharma a percentage, in the low double-digits, of the sublicensing revenue we receive under such agreement. In September 2023, we and Sutro Biopharma amended certain terms of the Sutro Biopharma License Agreement, including with respect to (i) royalty reduction provisions applicable in the event of expiration of relevant patent claims, which would result in lower royalties payable by us to Sutro Biopharma under certain circumstances, (ii) the ownership, prosecution, maintenance and enforcement of certain intellectual property rights licensed or arising under the Sutro Biopharma License Agreement (including as agreed to be amended in the Option Agreement (as defined below)), and (iii) the timing and form for financial reporting of royalty payment calculations. The Sutro Biopharma License Agreement will remain in effect until terminated. The agreement may be terminated by either party for the other party’s material breach uncured within 60 days’ notice, by us at will with 60 days’ notice, or by Sutro Biopharma if we challenge Sutro Biopharma’s patents or if we undergo a change of control with a specified competitor of Sutro Biopharma. Supply Agreement In May 2018, we entered into a supply agreement with Sutro Biopharma, which was subsequently amended on February 22, 2021 and November 21, 2023 (as amended, the “Sutro Biopharma Supply Agreement”) pursuant to which we purchase from Sutro Biopharma extract and custom reagents for use in manufacturing non-clinical and certain clinical supply of vaccine compositions utilizing the technology licensed under the Sutro Biopharma License at prices not to exceed a specified percentage above Sutro Biopharma’s fully burdened manufacturing cost. If any extracts or custom reagents do not meet the specifications and warranties provided, then we will not have an obligation to pay for the non-conforming product, and Sutro Biopharma will be obligated to replace the non-conforming product within the shortest possible time with conforming product at our cost. The term of the Sutro Biopharma Supply Agreement is from execution until the later of (i) July 31, 2022, or (ii) the date that we and Sutro Biopharma enter into the Phase 3/Commercial Supply Agreement and 28 Table of Contents Sutro Biopharma is supplying to us each Product under the Phase 3/Commercial Supply Agreement (each term as defined in the Sutro Biopharma Supply Agreement). The Sutro Biopharma Supply Agreement may be terminated by either party for the other party’s material breach uncured within 60 days’ notice, by us at will with 60 days’ notice, or by mutual agreement of the parties. In December 2019, we exercised our right to require Sutro Biopharma to establish a second supplier for extract and custom reagents to support our anticipated clinical and commercial needs. Option Agreement In December 2022, we entered into an option grant agreement with Sutro Biopharma (the “Option Agreement”). Pursuant to the Option Agreement, we acquired from Sutro Biopharma (i) authorization to enter into an agreement with an independent alternate contract manufacturing organization (“CMO”) to directly source Sutro Biopharma’s cell-free extract, allowing us to have direct oversight over financial and operational aspects of the relationship with the CMO; and (ii) a right, but not an obligation, to obtain certain exclusive rights to internally manufacture and/or source extract from certain CMOs and the right to independently develop and make improvements to extract (including the right to make improvements to the extract manufacturing process as well as cell lines) for use in connection with the exploitation of certain vaccine compositions (the “Option”). We and Sutro Biopharma agreed to negotiate the terms and conditions of a form definitive agreement to be entered into in the event we exercise the Option, which would include the terms and conditions set forth in an executed term sheet between us (the “Term Sheet”) and such terms that were necessary to give effect to each of the terms and conditions set forth in the Term Sheet (the “Form Definitive Agreement”). As consideration for the Option and other rights and authorizations granted to us under the Option Agreement, we paid Sutro Biopharma upfront consideration of $22.5 million, consisting of (i) $10.0 million in cash and $7.5 million worth of shares of our common stock (the number of shares calculated based on the arithmetic average of the daily volume weighted average price of our common stock as traded on Nasdaq in the three consecutive trading days immediately prior to the issuance thereof) in December 2022, and (ii) $5.0 million in October 2023 within five business days after we and Sutro Biopharma mutually agree in writing upon the Form Definitive Agreement on September 28, 2023. The 167,780 shares of common stock issued was recorded at fair value of $8.0 million on the date of settlement, December 22, 2022. On November 21, 2023 (the “Option Exercise Date”), we exercised the Option by submitting written notice thereof to Sutro Biopharma and concurrently paid Sutro Biopharma $50.0 million in cash as the first of two installment payments for the Option exercise price, followed by the second and final installment of $25.0 million in cash in May 2024. We determined there was no current alternative future use of the acquired manufacturing rights from the Option Agreement and, as a result, the amounts paid were expensed as incurred. Upon the occurrence of certain regulatory milestones, certain additional milestone payments may total up to $60.0 million in cash. In the event that we undergo a change of control, certain rights and payments may be accelerated. Manufacturing Rights Agreement Concurrent with the payment of the first installment of the Option exercise price pursuant to the Option Agreement, on November 21, 2023, the manufacturing rights agreement (in the form of the Form Definitive Agreement) between us and Sutro Biopharma (the “Manufacturing Rights Agreement”) became effective. Under the Manufacturing Rights Agreement, we received an exclusive (except as to Sutro Biopharma), perpetual (subject to termination), worldwide license, for no additional royalty (i.e., royalty-free, other than any royalties due under the Sutro Biopharma License Agreement), under Sutro Biopharma’s relevant patents and know-how, to manufacture or have manufactured extract and improvements to extract (in any form) solely for use in the research, development, use, production, sale, offering for sale, export, import, commercialization or other exploitation of Vaccine Compositions (as defined in the Sutro Biopharma License Agreement) as well as certain rights with respect to certain regulatory matters related to extract and its use in connection with such Vaccine Compositions. We have the right to extend our rights and obligations under the Manufacturing Rights Agreement to our affiliates and to sublicense our rights to manufacture extract and improvements to extract to certain third-party CMOs and other contractors (for our benefit and not for such third party’s independent commercial use). For clarity, we are not permitted to manufacture extract for sale to third parties for the independent use of such third parties. Under the Manufacturing Rights Agreement, we have the obligation to protect the confidentiality of the extract manufacturing technology, and Sutro Biopharma has certain audit rights in connection therewith. Under the Manufacturing Rights Agreement, upon our request and at our cost, Sutro Biopharma will support up to two technology transfers to us (or to an affiliate of ours or certain third-party CMOs designated by us) of certain Sutro Biopharma know-how, materials and information to enable us to manufacture or have manufactured extract. Under certain circumstances, Sutro Biopharma may source extract from us or certain third-party CMOs, subject to reimbursement for technology transfer costs. 29 Table of Contents The Manufacturing Rights Agreement contains certain terms with respect to the ownership, prosecution, maintenance and enforcement of certain intellectual property rights licensed or arising under the Manufacturing Rights Agreement, which are generally consistent with the Sutro Biopharma License Agreement. Unless earlier terminated, the Manufacturing Rights Agreement will remain in effect in perpetuity. Sutro Biopharma may only terminate the Manufacturing Rights Agreement in the event of our (i) uncured, intentional, material breach of certain confidentiality provisions resulting in actual, material harm to Sutro Biopharma’s business, (ii) uncured, intentional material breach of certain provisions relating to the use of certain of Sutro Biopharma’s know-how outside of the Vaccine Field, (iii) unintentional, material breach of certain provisions relating to the use of certain of Sutro Biopharma’s know-how outside of the Vaccine Field that we do not use reasonable best efforts to cease and (to the extent reasonably curable) cure in a timely fashion, or (iv) uncured failure to pay the Option exercise price or any undisputed milestone payment under the Option Agreement when due. We may terminate the Manufacturing Rights Agreement at our discretion upon 60 days’ written notice, and both parties may terminate the Manufacturing Rights Agreement upon mutual written consent. Thermo Fisher Scientific Commercial Manufacturing and Supply Agreement On September 24, 2025, we entered into a master services agreement with Patheon Manufacturing Services LLC, part of Thermo Fisher Scientific (collectively, “Thermo Fisher”), pursuant to which Thermo Fisher will formulate, fill, inspect, package, label, test, manufacture and supply drug product for us at Thermo Fisher’s facility in Greenville, North Carolina (the "Thermo Fisher Commercial Manufacturing and Supply Agreement"). Pursuant to the Thermo Fisher Commercial Manufacturing and Supply Agreement, we have agreed to order drug product from Thermo Fisher based on certain binding forecast periods and established prices. In addition, we will also pay Thermo Fisher for technology transfer activities and reimburse Thermo Fisher for certain out-of-pocket capital expenditures under the terms of the agreement. The Thermo Fisher Commercial Manufacturing and Supply Agreement has an initial term of 15 years and will automatically renew for additional three-year periods unless either party provides notice of non-renewal before the end of the then existing term, subject to completion of ongoing services. We are permitted to terminate the Thermo Fisher Commercial Manufacturing and Supply Agreement prior to expiration, subject to the payment of applicable termination fees, plus certain capital expenditure commitments. Impact of Certain Trends and Macroeconomic Environment We operate in an industry that is subject to significant government regulation. Our operations are subject to significant risk and uncertainties, including financial, operational, technological, regulatory and political risks. Such factors include, but are not necessarily limited to, the results of clinical testing and trial activities; our ability to adequately demonstrate sufficient safety, tolerability and immunogenicity or efficacy of our vaccine candidates; our ability to enroll subjects in our ongoing and future clinical trials; our ability to successfully manufacture and supply our vaccine candidates for clinical trials or for future potential commercialization; our ability to obtain additional capital to finance our operations; our ability to obtain, maintain and protect our intellectual property rights; developments relating to our competitors and our industry, including competing vaccine candidates; the ability to obtain regulatory approval; the necessary requirements for regulatory approval; the ability to obtain favorable licensing, manufacturing or other agreements; the political and regulatory environment; general and market conditions; and other risks and uncertainties, including those more fully described in the “Risk Factors” section of this Quarterly Report on Form 10-Q. The trends towards rising inflation may materially adversely affect our business and corresponding financial position and cash flows. Inflationary factors, such as increases in the cost of our clinical trial materials and supplies, fluctuating interest rates and increases in overhead costs may adversely affect our operating results. Fluctuating interest rates and rising inflation rates also present a challenge impacting the U.S. economy and could make it more difficult for us to obtain traditional financing on acceptable terms, if at all, in the future. We may experience increases in our operating costs in the near future, including our labor costs and research and development costs, due to rising inflation, tariffs, supply chain constraints, and civil and political unrest in certain countries and regions. 30 Table of Contents Components of Results of Operations Operating Expenses Research and Development Research and development expenses represent costs incurred in performing research, development and manufacturing activities in support of our own product development efforts. Our research and development expenses include internal personnel-related costs (including salaries, employee benefits and stock-based compensation) for our personnel in research and development functions, and external costs including (i) product manufacturing costs, primarily related to acquiring, developing and manufacturing supplies for clinical trials and to prepare for potential future commercial launches, including fees paid to contract manufacturing organizations; (ii) clinical costs related to agreements with contract research organizations , investigative sites and consultants to conduct non-clinical and preclinical studies and clinical trials; (iii) research and development consumables, laboratory supplies and equipment costs; (iv) facility and other allocated shared services; and (v) other expenses primarily including professional and consulting services costs. Our PCV programs include VAX-31, VAX-24 and VAX-XL, and our non-PCV programs include VAX-A1, VAX-GI, and other discovery-stage programs. In August 2025, we announced that we paused the advancement, beyond preclinical development, of VAX-A1 and VAX-GI while remaining confident in their potential and preserving the option to advance the programs in the future. In June 2026, we initiated a Phase 1 adult study for VAX-A1. The majority of our external costs relate to our PCV programs compared to the costs related to non-PCV programs. Most of the external costs associated with our vaccine candidates, particularly our PCV programs, are common in nature, and can be deployed across multiple candidates or redeployed as our vaccine development strategy evolves; as a result, we do not track external costs by candidate, program or project. We do not allocate internal personnel-related costs by program or project because several of our departments support multiple vaccine candidate programs and the hours are not tracked separately by program. VAX-31 and VAX-24 are in the clinical stages, and VAX-XL and our non-PCV programs are in preclinical stages. The majority of our external costs relate to our clinical-stage programs compared to the costs related to our preclinical-stage programs. Costs associated with preclinical programs are relatively small and insignificant to the overall financial statements. Further, several expenses are shared among various vaccine programs and, as such, we do not separately track external costs by clinical and preclinical stages. Research and development expenses are expensed as incurred. Non-refundable advance payments for services that will be used or rendered for future research and development activities are recorded as prepaid expenses and recognized as expenses as the related services are performed. We expect our research and development expenses to increase in absolute dollars for the foreseeable future as we advance our vaccine candidates into and through preclinical studies and clinical trials, manufacture drug product for our clinical trials and to support the potential initial commercial launch of VAX-31 in the adult population, scale up our manufacturing activities, establish additional manufacturing capacity to meet potential incremental supply requirements following the potential commercial launches of VAX-31 in the adult population and VAX-31 or VAX-24 in the pediatric population, pursue regulatory approval of our vaccine candidates and expand our pipeline of vaccine candidates. The process of conducting the necessary preclinical and clinical research and completing the manufacturing requirements to obtain regulatory approval is costly and time-consuming. The actual probability of success for our vaccine candidates may be affected by a variety of factors, including the safety and efficacy or immunogenicity of our vaccine candidates, clinical data, investment in our clinical programs, competition, manufacturing capabilities and commercial viability. We may never succeed in achieving regulatory approval for any of our vaccine candidates. As a result of the uncertainties discussed above, we are unable to determine the duration and completion costs of our research and development projects or if, when and to what extent we will generate revenue from the commercialization and sale of our vaccine candidates. We accrue for costs related to research and development activities based on our estimates of the services received and efforts expended pursuant to quotes and contracts with vendors, including CMOs and CROs, that conduct research, development and manufacturing activities on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our vendors exceed the level of services provided and result in a prepayment of the research and development expense. Advance payments for goods and services to be used in future research and development activities are expensed when the activity has been performed or when the goods have been received. We make significant judgments and estimates in determining accrued research and development liabilities as of each reporting period based on the estimated time period 31 Table of Contents over which services will be performed and the level of effort to be expended. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual or prepaid expense accordingly. Although we do not expect our estimates to be materially different from amounts actually incurred, if our estimates of the status and timing of services performed differ from the actual status and timing of services performed, it could result in us reporting amounts that are too high or too low in any particular period. Our research and development costs may vary significantly based on factors such as: •the costs and timing of our CMC activities, including fulfilling good manufacturing practice (“GMP”) related standards and compliance, and identifying and qualifying second suppliers; •the costs related to raw materials we purchase directly or through our third-party manufacturing and supply partners; •the cost of clinical trials of our vaccine candidates; •changes in the standard-of-care on which a clinical development plan was based, which may require new or additional trials; •the number of sites included in the trials; •the countries in which the trials are conducted; •delays in adding a sufficient number of trial sites and recruiting suitable volunteers to participate in our clinical trials; •the number of subjects that participate in the trials; •the number of doses that subjects receive; •subjects dropping out of a study or lost in follow-up; •potential additional safety monitoring requested by regulatory agencies; •the duration of subject participation in the trials and follow-up; •the cost and timing of manufacturing our vaccine candidates; •the phase of development of our vaccine candidates; •the costs of establishing additional manufacturing capacity to meet potential incremental supply requirements following the potential commercial launches of VAX-31 in the adult population and VAX-31 or VAX-24 in the pediatric population; •the costs that may be required for secondary supply sources; and •the immunogenicity or efficacy and safety and tolerability profile of our vaccine candidates. General and Administrative General and administrative expenses consist primarily of costs and expenses related to personnel (including salaries, employee benefits and stock-based compensation) in our executive, legal, finance and accounting, human resources and other administrative functions; legal services relating to intellectual property and corporate matters; accounting, auditing, consulting and tax services; insurance; and facility and other allocated shared costs not otherwise included in research and development expenses. We expect our general and administrative expenses to continue to increase in absolute dollars for 32 Table of Contents the foreseeable future as we increase our headcount and expand our services to support our continued research and development activities and grow our business. Other Income (Expense), Net Other income (expense), net includes interest income earned from our cash, cash equivalents and investments, grant income and foreign currency transaction gains (losses) related to our Swiss Franc and Euro cash and liability balances, loss on disposals of fixed assets and interest expense. Interest Income Interest income is earned from our cash and cash equivalents balances and short- and long-term investments. The cost of investment securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in other income, net. Realized gains and losses are also included in other income, net. When the fair value of a debt security declines below its amortized cost basis, any portion of that decline attributable to credit losses, to the extent expected to be nonrecoverable before the sale of the security, is recognized in our condensed consolidated statements of operations. When the fair value of a debt security declines below its amortized cost basis due to changes in interest rates, such amounts are recorded in other comprehensive loss, and are recognized in our condensed consolidated statements of operations only if we sell or intend to sell the security before recovery of its cost basis. Grant Income Our vaccine development program for VAX-A1, a novel conjugate vaccine candidate designed to prevent disease caused by Group A Streptococcus, has been funded in part by a grant obtained from Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator (“CARB-X”), a global non-profit partnership dedicated to accelerating antibacterial innovation to tackle the rising global threat of drug-resistant bacteria. The CARB-X grant provided funding of $11.7 million upon the achievement of VAX-A1 development milestones through June 2024. As of the second quarter of 2024, all of these milestones had been successfully achieved, and no further amounts will be funded under this CARB-X grant. Our vaccine development program for VAX-GI, a novel preclinical vaccine candidate being developed as a preventative treatment for dysentery and shigellosis, which is caused by Shigella bacteria, is currently funded in part by two grants obtained from the NIH administered by the University of Maryland, Baltimore. Our first grant from the NIH was awarded in April 2021 and provides for potential funding up to five years totaling approximately $0.5 million. In June 2023, we received another grant from the NIH that provides for potential funding up to five years totaling approximately $4.6 million. As of June 30, 2026, we have received and expect to continue to receive funding under each of these grants. We are currently working on a discovery program with the University of North Carolina at Chapel Hill and the University of Chicago to develop a vaccine candidate for the prevention of Chlamydia, which is funded in part by a grant from the NIAID that provides potential funding up to five years totaling approximately $9.5 million. As of June 30, 2026, we have received and expect to continue to receive funding under this grant. Income from grants is recognized in the period during which the related specified expenses are incurred, provided that the conditions under which the grants were provided have been met. The amount of grant income was not material during the three and six months ended June 30, 2026 and June 30, 2025. Grant income is included as a component of Other income, net in the condensed consolidated statements of operations. 33 Table of Contents Results of Operations Comparison of the Three and Six Months Ended June 30, 2026 and 2025 The following table summarizes our results of operations for the periods presented: Three Months Ended June 30, Change Six Months Ended June 30, Change 2026 2025 $ % 2026 2025 $ % (in thousands) (in thousands) Operating expenses: Research and development $ 267,852 $ 194,179 $ 73,673 37.9 % $ 580,631 $ 342,313 $ 238,318 69.6 % General and administrative 34,925 32,040 2,885 9.0 % 67,996 64,699 3,297 5.1 % Total operating expenses 302,777 226,219 76,558 33.8 % 648,627 407,012 241,615 59.4 % Loss from operations (302,777) (226,219) (76,558) 33.8 % (648,627) (407,012) (241,615) 59.4 % Other income, net: Interest income 25,755 31,073 (5,318) (17.1) % 52,365 64,008 (11,643) (18.2) % Other income (expense) (7,280) 28,573 (35,853) (125.5) % (8,662) 35,713 (44,375) (124.3) % Total other income, net 18,475 59,646 (41,171) (69.0) % 43,703 99,721 (56,018) (56.2) % Net loss $ (284,302) $ (166,573) $ (117,729) 70.7 % $ (604,924) $ (307,291) $ (297,633) 96.9 % Operating Expenses Research and Development Expenses Three Months Ended June 30, Change Six Months Ended June 30, Change 2026 2025 $ % 2026 2025 $ % (in thousands) (in thousands) External costs: Product manufacturing costs $ 114,034 $ 90,852 $ 23,182 25.5 % $ 275,083 $ 148,129 $ 126,954 85.7 % Clinical trials-related expenses 43,114 17,679 25,435 143.9 % 104,994 34,515 70,479 204.2 % Research expenses 34,315 21,044 13,271 63.1 % 52,677 36,542 16,135 44.2 % Facility and other allocated costs 11,531 11,221 310 2.8 % 22,481 21,822 659 3.0 % Other external costs 5,850 3,934 1,916 48.7 % 10,041 7,527 2,514 33.4 % Total external costs 208,844 144,730 64,114 44.3 % 465,276 248,535 216,741 87.2 % Internal costs: Personnel-related expenses 59,008 49,449 9,559 19.3 % 115,355 93,778 21,577 23.0 % Total research and development expenses $ 267,852 $ 194,179 $ 73,673 37.9 % $ 580,631 $ 342,313 $ 238,318 69.6 % Research and development expenses increased by $73.7 million, or 37.9%, during the three months ended June 30, 2026, compared to the corresponding period in 2025. The increase was largely driven by external costs, which grew by $64.1 million primarily due to increased activities related to clinical trials and product manufacturing in connection with our PCV programs. Clinical trials-related expenses increased by $25.4 million primarily due to the activities associated with the VAX-31 OPUS-1, OPUS-2, and OPUS-3 Phase 3 studies. Product manufacturing costs increased by $23.2 million primarily driven by increased manufacturing activities to support the potential future commercial launches. Research expenses increased by $13.3 million, and other external costs increased by $1.9 million compared to the corresponding period in 2025. The increase was further driven by internal personnel-related costs, which grew by $9.6 million, primarily due to headcount growth. Research and development expenses increased by $238.3 million, or 69.6% during the six months ended June 30, 2026 compared to the corresponding period in 2025. The increase was driven by external costs, which grew by $216.7 million largely due to increased activities related to product manufacturing and clinical trials in connection with our PCV programs. Product manufacturing costs increased by $127.0 million due to an increase in manufacturing activities, including to support the potential future commercial launches, Clinical trials-related expenses increased by $70.5 million, primarily due to the initiation of and enrollment in the VAX-31 OPUS-1, OPUS-2 and OPUS-3 Phase 3 studies, Research expenses increased by $16.1 million, and other external costs increased by $2.5 million compared to the corresponding period in 2025. The increase was further driven by internal personnel-related costs, which grew by $21.6 million largely due to headcount growth. 34 Table of Contents General and Administrative Expenses General and administrative expenses increased by $2.9 million, or 9.0% during the three months ended June 30, 2026 compared to the corresponding period in 2025, which was driven primarily by an increase in internal personnel-related costs due to headcount growth. General and administrative expenses increased by $3.3 million, or 5.1%, during the six months ended June 30, 2026 compared to the corresponding period in 2025 which was driven primarily by an increase in internal personnel-related costs due to headcount growth Other Income, Net Other income, net decreased by $41.2 million, or 69.0%, during the three months ended June 30, 2026 compared to the corresponding period in 2025. The decrease was primarily attributable to a $35.9 million reduction in unrealized and realized foreign currency gains due to fluctuations in the foreign currency exchange rates and a $5.3 million decrease in interest income as a result of lower cash and investment balances and lower interest rates during the period. Other income, net decreased by $56.0 million, or 56.2%, during the six months ended June 30, 2026 compared to the corresponding period in 2025. The decrease was primarily attributable to a $44.4 million reduction in unrealized and realized foreign currency gains due to fluctuations in the foreign currency exchange rates and a $11.6 million decrease in interest income as a result of lower cash and investment balances and lower interest rates during the period. Liquidity and Capital Resources From inception through June 30, 2026, we have incurred losses and negative cash flows from operations and have funded our operations primarily through the issuance of common stock, pre-funded warrants to purchase our common stock and, prior to our IPO, redeemable convertible preferred stock, totaling approximately $5.3 billion in aggregate gross proceeds and $5.1 billion net of underwriting discounts, commissions and offering expenses. As of June 30, 2026, we had $0.2 billion in cash and cash equivalents, $2.3 billion in investments and an accumulated deficit of $2.8 billion. On July 2, 2021, we filed a shelf registration statement on Form S-3ASR (the “2021 Shelf Registration Statement”) under which we could, from time to time, sell securities in one or more offerings of our common stock, preferred stock, debt securities or warrants. The 2021 Shelf Registration Statement became automatically effective upon the filing of the Form S-3ASR on July 2, 2021, and was scheduled to expire on July 2, 2024. In anticipation of such expiration, we filed a new shelf registration statement on Form S-3ASR on May 24, 2024 solely to replace the 2021 Shelf Registration Statement (such replacement registration statement, the “2024 Shelf Registration Statement”). Pursuant to the 2024 Shelf Registration Statement, we may, from time to time, sell securities in one or more offerings of our common stock, preferred stock, debt securities or warrants. The 2024 Shelf Registration Statement became automatically effective upon the filing of the Form S-3ASR on May 24, 2024. ATM Program In July 2021, we entered into an Open Market Sales AgreementSM (the “Original ATM Sales Agreement”) with Jefferies LLC (“Jefferies”), which provided that, upon the terms and subject to the conditions and limitations set forth in the Original ATM Sales Agreement, we had the right to issue and sell, from time to time, shares of our common stock having an aggregate offering price of up to $150.0 million through Jefferies acting as our sales agent or principal. As of February 27, 2023, we had sold 4,995,709 shares of our common stock under the Original ATM Sales Agreement at a weighted average price of $27.57 per share for aggregate gross proceeds of $137.8 million. On February 27, 2023, we and Jefferies entered into an amendment to the Original ATM Sales Agreement (as amended, the “Amended ATM Sales Agreement”) pursuant to which we had the right to issue and sell, from time to time, shares of our common stock having an aggregate offering price of up to $400.0 million. Effective as of February 24, 2026, we terminated the Amended ATM Sales Agreement. Prior to termination, we sold 4,211,367 shares of our common stock under the Amended ATM Sales Agreement at a weighted average price of $64.19 per share for aggregate gross proceeds of $270.3 million ($264.2 million net of commissions and offering expenses). On February 24, 2026, we entered into a Sales Agreement (the "2026 ATM Sales Agreement") with Leerink Partners LLC ("Leerink Partners"), to issue and sell, from time to time at our discretion, shares of our common stock at an aggregate offering price up to $500.0 million through Leerink Partners as our sales agent. We will pay Leerink Partners a commission of up to 3.0% of the gross sales proceeds of any common stock sold through Leerink Partners under the 2026 ATM Sales Agreement; however, we are not obligated to make any sales of common stock. As of June 30, 2026, we have not sold any shares of our common stock under the 2026 ATM Sales Agreement. 35 Table of Contents Underwritten Follow-on Public Offerings From January 2022 through September 2024, we successfully completed a number of underwritten public offerings, which included pre-funded warrants to purchase a total of 10,458,434 shares of our common stock. The pre-funded warrants are exercisable, at the option of each holder, in whole or in part by delivering to us a duly executed exercise notice and payment of the exercise price. Each pre-funded warrant has an exercise price of $0.001 per share. No fractional shares of common stock will be issued in connection with the exercise of a pre-funded warrant. The holders of the pre-funded warrants may also satisfy their obligation to pay the exercise price through a “cashless exercise,” in which the holder receives the net value of the pre-funded warrant in shares of common stock determined according to the formula set forth in the pre-funded warrant. The pre-funded warrants will not expire until they are fully exercised. However, we may not effect the exercise of any pre-funded warrants, and a holder will not be entitled to exercise any portion of any pre-funded warrants that, upon giving effect to such exercise, would cause: (i) the aggregate number of shares of our common stock beneficially owned by such holder (together with affiliates) to exceed 4.99% or 9.99% of the number of shares of our common stock outstanding immediately after giving effect to the exercise, as applicable; or (ii) the combined voting power of our securities beneficially owned by such holder (together with its affiliates) to exceed 4.99% or 9.99% of the combined voting power of all of our securities outstanding immediately after giving effect to the exercise, as applicable, as such percentage ownership is determined in accordance with the terms of the pre-funded warrants. However, any holder of a pre-funded warrant may increase or decrease such percentage to any other percentage not in excess of 19.99% upon at least 61 days' prior notice for the holder to us. During the three and six months ended June 30, 2025, 640,705 and 4,140,705 shares underlying the pre-funded warrants were exercised, respectively, to receive 640,685 and 4,140,644 shares of common stock, respectively, net of exercise costs. No shares underlying the pre-funded warrants were exercised during the three and six months ended June 30, 2026. As of both June 30, 2026 and December 31, 2025, a total of 5,463,793 shares underlying pre-funded warrants were outstanding. In February 2026, we completed an underwritten public offering of 12,650,000 shares of our common stock, which included the full exercise of the underwriters’ option to purchase an additional 1,650,000 shares, at a price of $50.00 per share. In aggregate, we received $601.8 million in net proceeds after deducting underwriting discounts, commissions and other offering expenses payable by us. In July 2026, a total of 3,946,094 shares underlying the pre-funded warrants from various underwritten public offerings were exercised to receive 3,946,020 shares of common stock, net of exercise costs. Future Funding Requirements Our primary uses of cash are to fund our operations, which consist primarily of research, development and manufacturing expenditures related to our programs and, to a lesser extent, capital expenditures for our commercial manufacturing facility build-out and general and administrative expenditures. We anticipate that we will continue to incur significant expenses and capital expenditures for the foreseeable future as we continue to advance our vaccine candidates, expand our corporate infrastructure, further our research and development initiatives for our vaccine candidates, build out and operate our commercial manufacturing facilities, and scale our laboratory and manufacturing operations. We are subject to all of the risks typically related to the development of new drug candidates, and we may encounter unforeseen expenses, difficulties, complications, delays and other unknown factors that may adversely affect our business. We anticipate that we will need substantial additional funding in connection with our continuing operations. We believe that our existing cash, cash equivalents and investments as of the date of this Quarterly Report on Form 10-Q will be sufficient to fund our operating expenses and capital expenditure requirements through at least 12 months from the filing date of this Quarterly Report on Form 10-Q. We have raised substantial capital; however, we will need to raise substantial additional capital to complete development, manufacturing and commercialization of our drug candidates. Until we can generate sufficient revenue from the commercialization of our vaccine candidates or from collaboration agreements with third parties, if ever, we expect to finance our future cash needs through public or private equity or debt financings, third-party (including government) funding and marketing and distribution arrangements, as well as other collaborations, strategic alliances and licensing arrangements, or any combination of these approaches. The sale of equity, pre-funded warrants or convertible debt securities may result in dilution to our stockholders and, in the case of preferred equity securities or convertible debt, those securities could provide for rights, preferences or privileges senior to those of our common stock. Debt financings may subject us to covenant limitations or restrictions on our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. Our ability to raise additional funds may be adversely impacted by deteriorating global economic conditions, including higher inflation rates and changes in interest rates, and the recent disruptions to and volatility in the credit and financial markets in the United States and 36 Table of Contents worldwide. There can be no assurance that we will be successful in acquiring additional funding at levels sufficient to fund our operations or on terms favorable or acceptable to us. If we are unable to obtain adequate financing when needed or on terms favorable or acceptable to us, we may be forced to delay, reduce the scope of or eliminate one or more of our research and development programs. Our future capital requirements will depend on many factors, including: •the timing, scope, progress, results and costs of research and development, testing, screening, manufacturing, preclinical development and clinical trials; •the costs of establishing additional manufacturing capacity to meet potential incremental supply requirements following the potential commercial launches of VAX-31 in the adult population and VAX-31 or VAX-24 in the pediatric population; •the outcome, timing and cost of seeking and obtaining regulatory approvals from the FDA and comparable foreign regulatory authorities, which may require more studies than those that we currently expect or change their requirements regarding the data required to support a marketing application; •the cost of building a sales force in anticipation of any product commercialization; •the costs of future commercialization activities, including product manufacturing, marketing, sales, royalties and distribution, for any of our vaccine candidates for which we receive marketing approval; •our ability to maintain existing, and establish new, strategic collaborations, licensing or other arrangements and the financial terms of any such agreements, including the timing and amount of any future milestone, royalty or other payments due under any such agreement; •exchange rate fluctuations due to exposure of foreign operations and foreign currency fluctuations and translations; •any product liability or other lawsuits related to our products; •the revenue, if any, received from commercial sales, or sales to foreign governments, of our vaccine candidates for which we may receive marketing approval; •the costs to establish, maintain, expand, enforce and defend the scope of our intellectual property portfolio, including the amount and timing of any payments we may be required to make, or that we may receive, in connection with licensing, preparing, filing, prosecuting, defending and enforcing our patents or other intellectual property rights; •expenses needed to attract, hire and retain skilled personnel; and •the impact of macroeconomic factors, including potential effects of changes in federal government regulation, rising inflation which may impact labor costs, research and development costs, tariffs, and supply chain constraints, as well as civil and political unrest in certain countries and regions, which may exacerbate the magnitude of the factors discussed above. A change in the outcome of any of these or other variables could significantly change the costs and timing associated with the development of our vaccine candidates. Furthermore, our operating plans may change in the future, and we may need additional funds to meet operational needs and capital requirements associated with such change. 37 Table of Contents Cash Flows The following table summarizes our cash flows for the periods indicated: Six Months Ended June 30, 2026 2025 (in thousands) Net cash used in operating activities $ (513,096) $ (287,440) Net cash (used in) provided by investing activities (85,691) 201,059 Net cash provided by financing activities 607,284 3,277 Effect of exchange rate changes on cash and cash equivalents 733 1,972 Net increase (decrease) in cash, cash equivalents and restricted cash $ 9,230 $ (81,132) Net Cash Flows from Operating Activities Net cash used in operating activities for the six months ended June 30, 2026 was $513.1 million, an increase of $225.7 million compared to the six months ended June 30, 2025. The increase was primarily due to higher cash expenditures to support our business growth, including increased development and manufacturing activities in connection with the adult and infant PCV programs to support the potential future commercial launches, as well as timing of payments. Net Cash Flows from Investing Activities Net cash used in investing activities for the six months ended June 30, 2026 was $85.7 million, an increase of $286.8 million compared to net cash provided by investing activities for the six months ended June 30, 2025. The change was primarily attributable to a $189.3 million increase in purchases of investments and a $114.6 million decrease in maturities and sales of investments. Net Cash Flows from Financing Activities Net cash provided by financing activities for the six months ended June 30, 2026 was $607.3 million, an increase of $604.0 million compared to the six months ended June 30, 2025. The increase was primarily due to $601.8 million in net proceeds from the follow-on offering during the six months ended June 30, 2026, whereas no such offerings occurred during the six months ended June 30, 2025. Contractual Obligations and Commitments Our material cash requirements include the following contractual and other obligations: Leases We have operating lease agreements for our office spaces. As of June 30, 2026, we had total lease payment obligations of $158.2 million, of which $13.7 million is payable within one year. Option Agreement In November 2023 (the “Option Exercise Date”), we exercised the Option pursuant to the Option Agreement by submitting written notice thereof to Sutro Biopharma and paid Sutro Biopharma an aggregate of $75.0 million in cash for the Option exercise price, with the final payment made in May 2024. Upon the occurrence of certain regulatory milestones, we would be obligated to pay Sutro Biopharma certain additional milestone payments totaling up to $60.0 million in cash. In the event that we undergo a change of control, certain rights and payments may be accelerated. Purchase Commitments We have certain payment obligations under various license agreements. Under these agreements, we are required to make milestone payments upon successful completion and achievement of certain intellectual property, clinical, regulatory and sales milestones. The payment obligations under the license agreements are contingent upon future events such as our achievement of specified development, clinical, regulatory and commercial milestones, and we will be required to make 38 Table of Contents development milestone payments and royalty payments in connection with the sale of products developed under these agreements. As the achievement and timing of these future milestone payments are not probable or estimable, such amounts have not been included in our condensed consolidated balance sheets as of June 30, 2026 or December 31, 2025. We enter into agreements in the normal course of business with CMOs and other vendors for manufacturing services and raw materials purchases. We rely on several third-party manufacturers for our manufacturing requirements. As of June 30, 2026, we had the following amounts of non-cancelable purchase commitments related to manufacturing services and raw materials purchased due to our key manufacturing partners. These amounts represent our minimum contractual obligations, including termination fees. If we terminate certain firm orders with our key manufacturing partners, we will be required to pay for the manufacturing services scheduled or raw materials purchased under our arrangements. The actual amounts we pay in the future to the vendors under such agreements may differ from the purchase order amounts. Years ending December 31, (in thousands) Remainder of 2026 $ 394,161 2027 241,410 2028 24,118 2029 10,500 Thereafter — Total non-cancelable purchase commitments due to our key manufacturing partners $ 670,189 Critical Accounting Policies and Significant Judgments and Estimates Our condensed consolidated financial statements have been prepared in accordance with U.S. GAAP. The preparation of these condensed consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, expenses, and related disclosures. We base our estimates on historical experience and on various other assumptions that we believe are reasonable under the circumstances. We evaluate our estimates and assumptions on an ongoing basis. Actual results could differ materially from those estimates due to risks and uncertainty in the current economic environment. To the extent that there are material differences between these estimates and our actual results, our future consolidated financial statements will be affected. We believe the critical accounting estimates discussed under Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations" in our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 reflect our more significant estimates, assumptions, and judgments that have the most significant impact on our condensed consolidated financial statements. There have been no significant changes to our critical accounting estimates as filed in such report. Recently Adopted Accounting Pronouncements See Note 2, “Basis of Presentation and Summary of Significant Accounting Policies,” to our condensed consolidated financial statements included in Part I, Item 1 of this Quarterly Report on Form 10-Q for additional information.