Slide 1: Corporate Presentation
Corporate Presentation September 3, 2026
Slide 2: Forward-Looking Statements
Forward-Looking Statements This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements include, but are not limited to, statements related to the potential benefits of Vaxcyte’s carrier-sparing platform and vaccin
Slide 3: Vaxcyte Mission Statement
VAXCYTE MISSION STATEMENT We are on a global mission to engineer high- fidelity vaccines that protect humankind from the consequences of bacterial diseases. September 3, 2026 3
Slide 4: Highlights: Potential Best-in-Class PCV Franchise
Highlights: Potential Best-in-Class Pneumococcal Conjugate Vaccine (PCV) Franchise Enrollment Completed in VAX-31 OPUS-1 Phase 3, Noninferiority Trial Designed to Establish Fulsome Coverage for Adults POTENTIAL BEST-IN-CLASS HIGHLY ATTRACTIVE EXCLUSIVE CELL-FREE ALIGNED CRITICAL PCV FRANCHISE PCV MA
Slide 5: Cell-Free Protein Synthesis Platform Unlocks Multiple Vaccine Applications
Cell-Free Protein Synthesis Platform Unlocks Multiple Vaccine Applications Facilitates Design and Production of Proteins Beyond the Reach of Conventional Methods VAXCYTE CELL-FREE SPEED, FLEXIBILITY, SUPERIOR CONJUGATE NOVEL PROTEIN PROTEIN SYNTHESIS PLATFORM: XpressCF SCALABILITY VACCINES VACCINES
Slide 6: Pipeline of High-Fidelity Vaccines with Multiple Near-Term Milestones
Pipeline of High-Fidelity Vaccines with Multiple Near-Term Milestones Broad-Spectrum Conjugate and Novel Protein Vaccines to Prevent Bacterial Infectious Diseases Preclinical Phase 1 Phase 2 Phase 3 Approved Anticipated 2026 and 2027 Key Milestones 31-Valent Adults VAX-31 ADULT INDICATION VAX-31 Inf
Slide 7: Experienced Management Team with Track Record in Vaccines and Biopharma
Experienced Management Team with Track Record in Vaccines and Biopharma Grant Pickering, MBA Andrew Guggenhime, MBA Jim Wassil, MS, MBA Mike Mullette, MBA Chief Executive Officer, President Executive VP, Chief Operating Officer Chief Commercial Officer Director & Co-Founder & Chief Financial Officer
Slide 8: PCV Opportunity
PCV Opportunity VAXCYTE
Slide 9: Global Health Impact of Pneumococcal Disease Remains Significant
Global Health Impact of Pneumococcal Disease Remains Significant ABOUT STREPTOCOCCUS CURRENT ~$8 BILLION GLOBAL INCIDENCE & IMPACT PNEUMONIAE GLOBAL VACCINE CATEGORY OF PD STILL SUBSTANTIAL Streptococcus pneumoniae is the Vaccinations are recommended globally for infants Global pneumococcal disease
Slide 10: Serotype Replacement Drives Need for Broader-Spectrum Vaccines
Serotype Replacement Drives Need for Broader-Spectrum Vaccines Non-Vaccine Serotypes Increase in Prevalence, as Circulation of Vaccine Serotypes is Eliminated, Resulting in the Need for Broader-Spectrum Vaccines UK IPD CASES IN ADULTS > 651 30 Prevnar 13 Types Non-vaccine Types 25 Residual disease d
Slide 11: Limitations of Current PCVs
Limitations of Current PCVs Coverage Expansion Needed to Address Circulating Disease, but Protein Carrier Backbone Problematic LIMITATIONS OF CONVENTIONAL PROTEIN CARRIER DIVERTS IMMUNE RESPONSE 90 CHEMISTRY Protein Carrier (mcg) Discrete Pneumococcal Polysaccharides (ug) 84 • Random conjugation mas
Slide 12: Limitations of Current PCVs: Adding Conjugates Results in Lower Ab Titers
Limitations of Current PCVs: Adding Conjugates Results in Lower Ab Titers Coverage Expansion Using Conventional Chemistry Has Led to Carrier-Induced Immune Suppression CARRIER SUPPRESSION Diminished immune response to target polysaccharides due to cumulative amount of protein carrier • Expanded spec
Slide 13: Vaxcyte's PCV Franchise Employs Carrier-Sparing Conjugates
Vaxcyte’s PCV Franchise Employs Carrier-Sparing Conjugates Cell-Free Platform Enables Precise Conjugation to Enhance Potency of Standard Protein Carrier PROPRIETARY eCRM® PROTEIN CARRIER WITH VAXCYTE CARRIER-SPARING CONJUGATES PRECISE, SITE-SPECIFIC CONJUGATION SITES MIMIC THE CUSTOMARY MATRIX FORM
Slide 14: Vaxcyte PCV Franchise Design Leverages Many Standard PCV Conventions
Vaxcyte PCV Franchise Design Leverages Many Standard PCV Conventions Utilizes Proven Components, Chemistries and Assays to Reduce Risk and Uncertainty Polysaccharide Protein Carrier Assays Random Site-Specific CQA Serological CDAP / Periodate Amination for Incorporation of Lysine Click Chemistry Rel
Slide 15: Vaxcyte's PCV Franchise Has More Fulsome Coverage Versus On-Market PCVs
Vaxcyte’s PCV Franchise Has More Fulsome Coverage Versus On-Market PCVs Pneumococcal Vaccines Represent One of the Largest Segments of Global Vaccine Market, with Significant Growth Expected¹ VAX-31: 31-valent PCV, the broadest-spectrum PCV in the clinic, designed to cover both currently circulating
Slide 16: Pneumococcal Vaccine Market is Highly Attractive
Pneumococcal Vaccine Market is Highly Attractive Vaxcyte’s PCV Franchise Has the Potential to Be Best-in-Class Due to Broader Coverage and Improved Immunogenicity PNEUMOCOCCAL VACCINE MARKET DYNAMICS SEROTYPE & DISEASE COVERAGE ADVANTAGE IS PRIMARY DRIVER OF U.S. PCVs ARE HIGHLY EFFECTIVE DURABLE &
Slide 17: Pneumococcal Vaccine Market Poised for Significant Growth
Pneumococcal Vaccine Market Poised for Significant Growth Combined $8B Market Expected to Grow to ~$12B in 2030¹, Driven Primarily by Adult Market Expansion Future Market 2030: ~$12B EXPECTED ADULT SEGMENT GROWTH DRIVERS Pediatric market highly penetrated; significant growth opportunity in adult seg
Slide 18: Recent Burst of Adult PCV Recommendations Outside the U.S.
Recent Burst of Adult PCV Recommendations Outside the U.S. Serotype Epidemiology, Broad-Valency PCVs Driving New Recommendations and Shift from PPSV23 to PCVs Expanded Licensure of broader-spectrum PCVs is driving Global Adult PCV Adoption adult universal recommendations internationally Japan Switze
Slide 19: Commercial Strategy for U.S. Adult PCV Market
Commercial Strategy for U.S. Adult PCV Market Initial Focus on Retail Pharmacies and Large Health Systems ~50% of U.S. Adult PCV Volume is Concentrated in 50-60 Accounts¹ RETAIL PHARMACIES¹ IDNs / HEALTH SYSTEMS¹ PHYSICIAN OFFICES¹ ~45% ~35% ~20% 6 retail chains account for ~70-80% ~50 large health
Slide 20: Establishing Manufacturing Capacity and Robust Supply Chain
Establishing Manufacturing Capacity, Robust Supply Chain to Support Expected VAX-31 Adult U.S. Launch, Followed by U.S. Infant and Global Adult and Infant PCV Launches Global Commercial Manufacturing U.S. Fill-Finish Manufacturing Agreement with Lonza Agreement with Thermo Fisher • Relationship enco
Slide 21: VAX-31 Adult Clinical Program
New slide/format VAX-31 Adult Clinical Program
Slide 22: VAX-31 Designed to Expand Protection with Broadest Disease Coverage in Adults
VAX-31 Designed to Expand Protection with Broadest Disease Coverage in Adults Percentage of IPD and Non-Bacteremic Pneumococcal Pneumonia Covered by PCVs in U.S. Adults IPD1 ≥50 years Pneumococcal Pneumonia2 ≥50 years 100% 95% 100% 90% 90% 88% 82% 80% 80% 69% 70% 70% 59% 60% 60% 57% 50% 46% 50% 44%
Slide 23: VAX-31 Designed to Provide Comprehensive Coverage While Maintaining Immune Response
VAX-31 is Designed to Provide Comprehensive Coverage, While Maintaining or Improving Immune Response, Relative to Today’s SoC that Only Provides Partial Coverage Next Generation PCV Designed to Cover 95% of IPD and ~88% of Pneumococcal Pneumonia in U.S. Adults Aged 50+ with Potential to Provide an I
Slide 24: VAX-31 Adult Phase 3 Program
VAX-31 Adult Phase 3 Program September 3, 2026 24
Slide 25: VAX-31 OPUS Phase 3 Adult Program Overview
VAX-31 OPUS Phase 3 Adult Program Overview (Subject Enrollment: n=6,191) OPUS Clinical Program Designed to Support Potential BLA Filing; Enrollment Completed in OPUS-1, OPUS-2, and OPUS-3 Trials VAX-31 PHASE 3 STUDIES¹ ANTICIPATED TIMING 2025 2026 2027 Announce OPUS-1: Pivotal, Noninferiority Trial
Slide 26: OPUS-1 Phase 3 Noninferiority Trial in Adults
OPUS-1 Phase 3 Noninferiority Trial Evaluating VAX-31 for the Prevention of Invasive Pneumococcal Disease and Pneumonia in Adults (n=4,049 Dosed) Study Designed to Establish New Standard for Adult PCVs Through Head-to-Head Safety, Tolerability and Immunogenicity Comparisons of VAX-311 with PCV21 and
Slide 27: OPUS-1 Phase 3 Pivotal Noninferiority Trial Key Objectives
OPUS-1 Phase 3 Pivotal Noninferiority Trial Key Objectives Expected to Serve as Cornerstone of BLA Package for Potential Licensure in Adults VAX-31 IMMUNOGENICITY STUDY OBJECTIVES EVALUATION CRITERIA • Noninferiority compared with PCV21 and/or PCV20 for the 28 serotypes (STs) shared with either or >
Slide 28: OPA GMR Responses for VAX-31 (Phase 2) and PCV21 (Phase 3) vs PCV20
OPA GMR Responses for VAX-31 (Phase 2) and PCV21 (Phase 3) vs PCV20 VAX-31 GMRs Higher on 18 of 20 Common STs and 7 STs Achieved Statistically Higher Immune Responses¹ VAX-31 HIGH DOSE PHASE 2 NI STUDY VS PCV20: PCV21 PHASE 3 PIVOTAL NI STUDY VS PCV20: 20 Common STs (OPA GMRs) 11 Common STs (OPA GMR
Slide 29: VAX-31 Will Be Evaluated Based on Totality of Evidence
Consistent with Precedent, VAX-31 Will Be Evaluated Based on Totality of Evidence, Not a Tally of Noninferiority Hits or Misses WHAT THE FDA HAS CONSIDERED BASED ON TOTALITY OF EVIDENCE: BREADTH OF SEROTYPE AND MAGNITUDE OF DISEASE COVERAGE IMMUNE RESPONSE Incremental serotypes and circulating Robus
Slide 30: Clear Expectations Ahead of OPUS-1 Reflect Confidence
Clear Expectations Ahead of OPUS-1 Reflect Confidence in Delivering Best-in-Class Pneumococcal Vaccine VAX-31 VS. PCV20 VAX-31 VS. PCV21 High confidence based on data from Phase 2 head-to-head Expect strong performance based on triangulation of existing data +11 incremental serotypes +10 additional
Slide 31: OPUS-1 Readout Approaches from a Position of Strength
OPUS-1 Readout Approaches from a Position of Strength STRENGTHENED COMPETITIVE SETUP AND SUBSTANTIALLY MORE ST AND DISEASE COVERAGE THAN CURRENT STANDARD-OF-CARE PCVs VAX-31 is the only high- Across the industry, four The 0.67 noninferiority OPUS-1, OPUS-2, and valent, next-generation adult pneumoco
Slide 32: OPUS-2 Phase 3 Trial with Seasonal Influenza Vaccine
OPUS-2 Phase 3 Clinical Trial Evaluating VAX-31 Concomitantly Administered with Seasonal Influenza Vaccine (n=1,390 Dosed) Descriptive Study Evaluating Safety, Tolerability and Immunogenicity of VAX-31¹ when Administered Either Concomitantly with or One Month Following Administration of a Licensed S
Slide 33: OPUS-3 Phase 3 Trial in Previously Vaccinated Adults
OPUS-3 Phase 3 Clinical Trial Evaluating VAX-31 in Healthy Adults Who Have Previously Received a Pneumococcal Vaccine (n=752 Dosed) Descriptive Study Evaluating Safety, Tolerability and Immunogenicity of a Single Dose Of VAX-31¹ in Healthy U.S. Adults Aged 50 Years and Older with a History of Prior
Slide 34: OPUS-2 and OPUS-3 Phase 3 Clinical Trial Key Objectives
OPUS-2 and OPUS-3 Phase 3 Clinical Trial Key Objectives Descriptive Phase 3 Studies Designed to Demonstrate VAX-31’s Performance in Real-World Adult Use OPUS-2: PHASE 3 TRIAL EVALUATING VAX-31 CONCOMITANTLY ADMINISTERED WITH SEASONAL INFLUENZA VACCINE • Primary Objective: Assessing serotype-specific
Slide 35: Overview: VAX-31 Adult Phase 1/2 Study Results
Overview: VAX-31 Adult Phase 1/2 Study Results September 3, 2026 35
Slide 36: Positive VAX-31 Phase 1/2 Adult Data Published in Lancet Infectious Diseases
Positive VAX-31 Phase 1/2 Adult Data Published in Lancet Infectious Diseases Unprecedented Results Support Potential Best-in-Class PCV With Broadest Serotype and Disease Coverage Overall study results positive and met objectives Well tolerated, demonstrating a safety profile similar to PCV20 At all
Slide 37: VAX-31 Induced Robust Immune Responses for All Common STs
VAX-31 Induced Robust Immune Responses for All 20 Common STs Middle and High Doses Met OPA Response Noninferiority Criteria for All 20 Common STs Compared to PCV20 VAX-31 Low Dose VAX-31 Middle Dose VAX-31 High Dose¹ 1 1 1 3 3 3 4 4 4 5 5 5 6A 6A 6A 6B 6B 6B 7F 8 7F 8 7F 8 * 9V 10A * 9V 10A * 9V 10A
Slide 38: VAX-31 Induced Robust Immune Responses for All Incremental STs
VAX-31 Induced Robust Immune Responses for All 11 Incremental STs All Three Doses Met Superiority Criteria for All Incremental STs Compared to PCV20 100% VAX-31 Low Dose 100% VAX-31 Middle Dose 100% VAX-31 High Dose¹ 90% % difference with a > 4-fold 90% 90% OPA titer increase (95% CI) 80% 80% 80% 70
Slide 39: VAX-31 Full Six-Month Safety Data Similar to PCV20
VAX-31 Full Six-Month Safety Data Similar to PCV20 and Across Cohorts VAX-31 VAX-31 VAX-31 PCV20 Low Dose Middle Dose High Dose¹ NUMBER OF SUBJECTS WITH: 255 254 253 253 Unsolicited TEAE, n (%) 42 (16.5) 43 (16.9) 47 (18.6) 42 (16.6) Related Unsolicited TEAE, n (%) 7 (2.7) 11 (4.3) 17 (6.7) 12 (4.7)
Slide 40: PCV Infant Clinical Program
PCV Infant Clinical Program VAXCYTE
Slide 41: VAX-31 Designed to Expand Protection with Broadest Disease Coverage in Children
VAX-31 Designed to Expand Protection with Broadest Disease Coverage in Children Percentage of IPD and Pneumococcal Acute Otitis Media Covered by PCVs in U.S. Children IPD1 <5 years Pneumococcal Acute Otitis Media2 <5 years 100% 100% 96% 91% 90% 90% 80% 80% 70% 64% 70% 61% 60% 60% 50% 50% 44% 40% 40%
Slide 42: VAX-31 Broadest Serotype Coverage in Infants, ~91% of IPD
VAX-31 Designed to Deliver Broadest Disease and Serotype Coverage in Infants, Including ~91% of Invasive Pneumococcal Disease (IPD) in U.S. Children¹ VAX-31’s UNIQUE 11 STs: Across multiple adult and infant studies, Vaxcyte’s PCVs have shown strong immune responses across all incremental STs relativ
Slide 43: VAX-31 Broadest Coverage in Infants, ~96% of AOM
VAX-31 Designed to Deliver Broadest Disease and Serotype Coverage in Infants, Including ~96% of Pneumococcal Acute Otitis Media (AOM) in U.S. Children¹ VAX-31’s UNIQUE STs VS STANDARD-OF-CARE INFANT PCVs: Potential to Provide 35-62% Increase in AOM Coverage Compared to Current Standards-of-Care Infa
Slide 44: Healthcare Providers Confirm: Broader Coverage Wins in PCV Selection
Healthcare Providers Confirm: Broader Coverage Wins in PCV Selection U.S. pediatric and family medicine providers overwhelmingly favor broader-coverage PCVs and would take action to expand protection for infants.¹ BROAD PROTECTION PROVIDERS WOULD WILLINGNESS TO OTITIS MEDIA DRIVES HCP ADOPTION SWITC
Slide 45: VAX-31 Infant Clinical Program
VAX-31 Infant Clinical Program
Slide 46: Enrollment Completed in VAX-31 Infant Phase 2 Study
Enrollment Completed in VAX-31 Infant Phase 2 Study 3-Stage, Dose-Finding Study Evaluating Safety, Tolerability and Immunogenicity vs PCV20 in 900 Participants Stage 1: Dose Escalation (n=48) Stages 2 & 3: Main Study (n=900*) VAX-31 Stage 3: VAX-31 Optimized Dose (4.4mcg/3.3mcg) High Dose End Stage
Slide 47: Study Safety, Tolerability and Immunogenicity Key Outcome Measures
Study Safety, Tolerability and Immunogenicity Key Outcome Measures DAY 7 AFTER EACH DOSE 1 MONTH POST-DOSE 3 1 MONTH POST-DOSE 4 6 MONTHS POST-DOSE 4 • Solicited local reactions • Unsolicited adverse events (AE) • SAE, NOCI and MAAE • SAE, NOCI and MAAE SAFETY AND • Solicited systemic events • Serio
Slide 48: VAX-24 Infant Phase 2 Dose-Finding Study Final Results
VAX-24 Infant Phase 2 Dose-Finding Study Final Results September 3, 2026 48
Slide 49: Final VAX-24 Phase 2 Infant Study Results and Platform
Final VAX-24 Phase 2 Infant Study Results and Platform Demonstrate Potential to Achieve Broadest Coverage of Any Infant PCV On-Market Overall study results positive and met objectives Well tolerated, demonstrating a safety profile similar to PCV20 VAX-24 elicited substantial IgG, OPA and memory resp
Slide 50: VAX-24 Infant Phase 2 Dose-Finding Clinical Study (N=803)
VAX-24 Infant Phase 2 Dose-Finding Clinical Study (N=803) Randomized, Observer-Blind, Active-Controlled, Dose-Finding, Clinical Study to Evaluate Safety, Tolerability and Immunogenicity of VAX-24 vs. Standard-of-Care (PCV20) in 803 Healthy Infants All 36 VAX-24 subjects from Stage 1 proceeded to Sta
Slide 51: Three VAX-24 Doses Evaluated in Infant Phase 2 Study
Three VAX-24 Doses Evaluated in Infant Phase 2 Dose-Finding Study Identical to Doses Evaluated in VAX-24 Adult Program 12.8% 12.3% 10.7% 10.7% % of IPD in U.S. children 4.2% <5 yrs of age1 3.9% 3.9% 2.4% 1.0% 0.8% 1.3% 0.3% 0.3% 0.3% 0.3% 0.3% 0.0% 0.0% 0.0% 0.0% 0.0% 0.5% 0.5% 0.0% 19F 3 15B/C2 22F
Slide 52: Final 6-Month Safety Data from VAX-24 Phase 2 Study
Final 6-Month Safety Data from VAX-24 Phase 2 Study Safety Results Similar to PCV20 and Across Cohorts VAX-24 VAX-24 VAX-24 PCV20 Low Dose Mid Dose Mixed Dose NUMBER OF SUBJECTS 195 186 191 185 Unsolicited TEAE, n (%) 167 (85.6) 161 (86.6) 163 (85.3) 169 (91.4) Related Unsolicited TEAE, n (%) 6 (3.1
Slide 53: Final Post-Dose 3 (PD3) IgG and OPA Immunogenicity Data Results
Final Post-Dose 3 (PD3) IgG and OPA Immunogenicity Data Results September 3, 2026 53
Slide 54: VAX-24 PD3 Seroconversion Rates Compared to PCV20
POST-DOSE 3 RESULTS VAX-24 PD3 Seroconversion Rates Compared to PCV20 Met Precedent Phase 2 Noninferiority Criteria for 20 of 24 STs at Low and Mid Doses and 19 of 24 STs at Mixed Dose VAX-24 vs. PCV20: Difference in % of Subjects Meeting Predefined IgG Levels2 % of IPD in U.S. children <5 yrs of ag
Slide 55: VAX-24 PD3 OPA GMT Immune Responses
POST-DOSE 3 RESULTS VAX-24 PD3 OPA GMT Immune Responses Demonstrated Robust OPA Titers, Generally Consistent with IgG Responses 100000 VAX-24 Low Dose VAX-24 Mid Dose VAX-24 Mixed Dose 10000 PCV 20 OPA GMTs (95% CI) 1000 100 10 1 19F 22F 33F 7F 12F 23F 17F 15B 11A 10A 19A 18C 6B 6A 9N 20B 3 4 8 14 5
Slide 56: Final Post-Dose 4 (PD4) IgG and OPA Immunogenicity Data Results
Final Post-Dose 4 (PD4) IgG and OPA Immunogenicity Data Results OPA = opsonophagocytic activity; IgG = immunoglobulin G. September 3, 2026 56
Slide 57: VAX-24 Demonstrated High Overall Seroconversion Rates Across All Doses PD4
POST-DOSE 4 RESULTS VAX-24 Demonstrated High Overall Seroconversion Rates Across All Doses PD4 VAX-24 Low Dose VAX-24 Mid Dose VAX-24 Mixed Dose PCV20 100 % of subjects with predefined IgG levels (>0.35mcg/mL) 80 60 40 20 0 14 9N 20C 33F 8 1 2 15B 11A 10A 19A 18C 19F 22F 7F 12F 23F 17F 9V 3 4 5 6B 6
Slide 58: VAX-24 PD4 IgG GMRs Compared to PCV20
POST-DOSE 4 RESULTS VAX-24 PD4 IgG GMRs Compared to PCV20 Met Target Ph2 Noninferiority Criteria for Point Estimate of >0.6 on 19 of 24 STs at Mixed Dose and 18 of 24 STs at Mid Dose % of IPD in U.S. children IgG Geometric Mean Ratios for VAX-24 vs. PCV202 <5 yrs of age1 VAX-24 Low Dose (1.1mcg) VAX
Slide 59: VAX-24 PD4 OPA GMT Immune Responses
POST-DOSE 4 RESULTS VAX-24 PD4 OPA GMT Immune Responses Demonstrated Robust OPA Titers, Generally Consistent with IgG Responses 100000 VAX-24 Low Dose VAX-24 Mid Dose VAX-24 Mixed Dose 10000 PCV 20 OPA GMTs (95% CI) 1000 100 10 1 19F 22F 33F 7F 12F 23F 17F 15B 11A 10A 19A 18C 6B 6A 9N 20B 3 4 8 14 5
Slide 60: VAX-24 Demonstrated Robust Memory Responses
VAX-24 Demonstrated Robust Memory Responses Pre- vs Post-Dose 4 IgG GMCs VAX-24 Mid Dose Pre-Dose 4 VAX-24 Mid Dose Post-Dose 4 15 IgG GMCs mcg/mLs (95% CI) 10 5 0 19F 22F 33F 7F 12F 23F 15B 11A 10A 19A 18C 6B 6A 9N 20C 3 4 8 14 5 1 9V 17F 2 Serotypes Contained in PCV20 Non-PCV20 Serotypes GMC = geo
Slide 61: Expanded Analysis of Concomitant Flu Vaccination & Dose-Dependent Immune Responses
Expanded Analysis of Concomitant Flu Vaccination & Dose-Dependent Immune Responses September 3, 2026 61
Slide 62: VAX-24 PD4 IgG GMRs Including Subjects Who Received Flu Vaccination
POST-DOSE 4 RESULTS VAX-24 PD4 IgG GMRs Compared to PCV20 Including Subjects Who Received Flu Vaccination Consistently Improved Immunogenicity Responses Evidenced in Mid Dose IgG Geometric Mean Ratios for VAX-24 vs. PCV20 Population: 1 - IEP4 11A - IEP4 Immunogenicity Evaluable Population 1 - IEP4 +
Slide 63: Dose Response Evidenced PD4 Across Most Serotypes
POST-DOSE 4 RESULTS Dose Response Evidenced PD4 Across Most Serotypes Supports Dosing Strategy for Ongoing VAX-31 Infant Phase 2 Study DOSE-DEPENDENT IMMUNOGENICITY LITTLE TO NO CARRIER SUPPRESSION EVIDENCED BY OBSERVED ACROSS DOSE RANGE1 SIMILAR PERFORMANCE ACROSS DIFFERENT LEVELS OF PROTEIN CARRIE
Slide 64: Group A Strep Opportunity & VAX-A1 Clinical Program
New slide/format Group A Strep Opportunity & VAX-A1 Clinical Program
Slide 65: Group A Strep: Among the World's Most Significant Bacterial Pathogens
Group A Strep: Among the World’s Most Significant Bacterial Pathogens Streptococcus pyogenes, or Group A Strep, is a pathogen that causes a wide array of disease from common acute infections to chronic conditions, resulting in a significant public health burden GROUP A STREP IS A GRAM (+) BACTERIUM
Slide 66: Group A Strep Infection Rates Have Increased Substantially
Group A Strep Infection Rates Have Increased Substantially HIGH RATES OF INVASIVE GROUP A STREP SIGNIFICANT INCREASE IN PHARYNGITIS RATES POST-COVID PANDEMIC IN THE U.S. POST-COVID PANDEMIC IN THE U.S.² Annual Rates of Invasive Group A Strep Infections in the U.S.¹ Percentage of Encounters for Phary
Slide 67: Growing Threat of Antibiotic Resistance Against Group A Strep
Growing Threat of Antibiotic Resistance Against Group A Strep Group A Strep Drives Significant Antibiotic Use, Especially Among Children, Contributing to Rising Antimicrobial Resistance RISING ANTIBIOTIC RESISTANCE FALLING TREATMENT CAPACITY Antibiotic resistance to Group A Strep has Group A Strep d
Slide 68: VAX-A1, a Potential Best-in-Class Group A Strep Vaccine Candidate
VAX-A1, a Potential Best-in-Class Vaccine Candidate Designed to Provide Broad Protection Against Disease Caused by Group A Strep VAX-A1 IS DESIGNED TO: Provide broad, strain-independent protection via a disease-specific protein Leverage cell-free protein synthesis platform to enable site-specific ca
Slide 69: VAX-A1: Conjugate Vaccine with Multiple Modes of Action
VAX-A1: Conjugate Vaccine with Multiple Modes of Action Protein-Polysaccharide Conjugate Protein Components SpyAD & Universal Polysaccharide (GACPR)¹ Streptolysin O (SLO) SpyAD, a surface-expressed highly-conserved antigen needed for A pore-forming cytolysin; Infiltrating Neutrophil/Phagocyte adhesi
Slide 70: VAX-A1 Phase 1 Two-Stage Dose-Escalation Study
Phase 1 Two-Stage, Dose-Escalation Study Evaluating VAX-A1 in Adults: Currently Enrolling 18-40 yr olds (n~80) Stage 1: Dose Escalation (n~12) Stage 2: Main Study (n~68) VAX-A1 High Dose: n~3 VAX-A1 High Dose: (n~17) Randomize (1:1:1:1) Placebo: n~1 VAX-A1 Mid Dose: (n~17) Randomize (3:1) DSMB Revie
Slide 71: VAX-A1 Phase 1 Study Key Objectives
VAX-A1 Phase 1 Study Key Objectives Primarily Designed to Assess Safety and Tolerability, with Secondary Objective to Assess Immune Responses DAY 7 1 MONTH 8 MONTHS ENTIRE DURATION PRIOR TO EACH DOSE (AFTER EACH DOSE) (AFTER EACH DOSE) (AFTER DOSE 1) OF STUDY • Solicited local reactions • Unsolicite
Slide 72: VAX-A1 Preclinical Data Published in Infectious Microbes & Diseases
VAX-A1 Preclinical Data Published in Infectious Microbes & Diseases¹ Supported Advancement into the Clinic In This Study, VAX-A1 Demonstrated Protective Immunity Against Group A Strep in Preclinical Systemic and Skin Infection Models MICE IMMUNIZED WITH VAX-A1 YIELDED 100% OBJECTIVE • The study exam
Slide 73: Shigella: VAX-GI Preclinical Program
New slide/format Shigella: VAX-GI Preclinical Program
Slide 74: VAX-GI: Shigella Vaccine Program
VAX-GI: Shigella Vaccine Program Novel Shigella Vaccine to Prevent Widespread Global Morbidity & Mortality, Particularly in Children UNMET • Shigella is a bacterial illness with no available preventative treatment NEED • Estimated to cause 80-165 million cases of disease and 600,000 deaths annually,
Slide 75: Key Corporate Highlights
Key Corporate Highlights Large Market Opportunity for Broadest-Spectrum PCV Cell-Free Protein Synthesis Enabled Pipeline Aligned Critical Commercial Manufacturing and Supply Chain Resources Robust Pipeline with Multiple Novel Vaccines September 3, 2026 75
Slide 76: Appendix
Appendix September 3, 2026 76
Slide 77: Spectrum of Coverage Drives Adoption in PCV Segment
Spectrum of Coverage Drives Adoption in PCV Segment VAX-31 Designed to Increase Coverage to ~95% of IPD Circulating in U.S. Adults 20.00% 18.5% 18.00% VAX-31: 16.00% • Positioned to provide unrivaled IPD coverage as the broadest-spectrum PCV to enter U.S. clinics; designed to increase coverage to ap
Slide 78: Spectrum of Coverage Drives Adoption in Vital Pediatric Population
Spectrum of Coverage Drives Adoption in Vital Pediatric Population Pediatric Segment Represents Majority of ~$8B Pneumococcal Vaccine Market VAX-24: Broadest-spectrum profile designed to cover more serotypes than any pediatric pneumococcal vaccine 14.00% 12.8% on-market today. 12.3% 12.00% VAX-31: 3
Slide 79: On-Market PCVs Elicit Antibodies for Disease Protection With Range of Results
On-Market PCVs Elicit Antibodies for Disease Protection With Range of Results Serotype 3 (ST3) Conjugate Elicits Weakest Antibody Response Among All Conjugates KEY FACTORS DETERMINE WHY ST3 REQUIRES HIGHER LEVEL OF PROTECTIVE ANTIBODY • Thick Polysaccharide Capsule: serotype 3 forms a robust physica
Slide 80: Contact
Contact: Jeff Macdonald, Executive Director, Investor Relations investors@vaxcyte.com