Vaxcyte Reports Positive Topline Data from Phase 1/2 Proof-of-Concept Study of its 24-Valent Pneumococcal Conjugate Vaccine Candidate Being Investigated for the Prevention of Invasive Pneumococcal Disease in Adults Aged

Vaxcyte Reports Positive Topline Data from Phase 1/2 Proof-of-Concept Study of its 24-Valent Pneumococcal Conjugate Vaccine Candidate Being Investigated for the Prevention of Invasive Pneumococcal Disease in Adults Aged 18-64

In the Study, VAX-24 Demonstrated a

Safety and Tolerability Profile Similar to Prevnar 20TM (PCV20) at All Doses Studied

All 24 Serotypes of VAX-24 at Conventional 2.2mcg PCV Dose Met or Exceeded Regulatory

Immunogenicity Standards

All 20 VAX-24 Serotypes Common with PCV20 Met

Standard OPA Response Non-Inferiority Criteria, of Which 16 Achieved Higher Immune Responses, at 2.2mcg VAX-24 Dose

All 4 Serotypes Unique to VAX-24 Exceeded Standard Superiority Criteria

Vaxcyte to Advance Potential

Best-in-Class VAX-24 Clinical Program in Adult and Pediatric Populations

Company to Host Webcast/Conference Call Today at 8:00 a.m. ET / 5:00 a.m. PT

SAN CARLOS, Calif., October 24, 2022 Vaxcyte, Inc. (Nasdaq: PCVX), a clinical-stage vaccine innovation company engineering

high-fidelity vaccines to protect humankind from the consequences of bacterial diseases, today announced positive topline results from the Phase 1/2 clinical

proof-of-concept study evaluating the safety, tolerability and immunogenicity of VAX-24, the Company s investigational 24-valent pneumococcal conjugate vaccine (PCV), in healthy adults aged 18-64. In this study, VAX-24 met the primary safety and

tolerability objectives, demonstrating a safety profile similar to Prevnar 20TM (PCV20) for all doses studied.

In the study, VAX-24 met or exceeded the established regulatory immunogenicity standards for all 24 serotypes at the

conventional 2.2mcg dose, which the Company intends to move forward into a Phase 3 program. At this dose, VAX-24 met the standard opsonophagocytic activity (OPA) response

non-inferiority criteria for all 20 serotypes common with PCV20, of which 16 achieved higher immune responses. Additionally, at all three doses, VAX-24 met the standard

superiority criteria for all four serotypes unique to VAX-24. These four incremental serotypes cover 10-15 percent of strains causing invasive pneumococcal disease

(IPD) over the current standard-of-care in adults.

We are thrilled with these positive topline results from our Phase 1/2

proof-of-concept study, which met all of our objectives. The findings indicate a potential

best-in-class profile for VAX-24 and validate our carrier-sparing approach to enable the development of broader-spectrum

PCVs, said Grant Pickering, Chief Executive Officer and Co-Founder of Vaxcyte. The study results demonstrate that VAX-24 has the potential to provide broader

coverage and better immune responses relative to the standard-of-care. We believe this presents an opportunity to set a new bar for immunogenicity standards for

pneumococcal vaccines.

Key Topline Study Results

Safety and Tolerability Findings:

Immunogenicity Findings:

We are very excited to share these strong clinical results from our

proof-of-concept study, which validate the potential for VAX-24 to improve upon the standard-of-care for adults by potentially providing 10-15 percent incremental protection for this serious disease. The 24 serotypes included in VAX-24 cover a significant portion of the IPD currently in circulation and are associated with high case-fatality rates, antibiotic resistance and meningitis, said Jim Wassil, Executive Vice President and

Chief Operating Officer of Vaxcyte. On behalf of our team at Vaxcyte, we would like to gratefully acknowledge the efforts of everyone involved in this program, especially the trial investigators, trial sites and study participants.

About the Phase 1/2 Clinical Proof-of-Concept Study

The VAX-24 Phase 1/2 clinical

proof-of-concept study is a randomized, observer-blind, dose-finding, controlled study designed to evaluate the safety, tolerability and immunogenicity of VAX-24 in healthy adults 18-64 years of age.

The Phase 1 portion of the study evaluated the safety and tolerability of a single injection of VAX-24 at three dose levels, 1.1mcg, 2.2mcg and 2.2mcg/4.4mcg, and compared to PCV20 in 64 healthy adults 18 to 49 years of age.

The Phase 2 portion evaluated the safety, tolerability and immunogenicity of a single injection of VAX-24 at the same

three dose levels and compared to a single injection of PCV20 in 771 healthy adults 50 to 64 years of age. The immunogenicity objectives of the Phase 2 portion of the study include an assessment of the induction of antibody responses, using OPA and

IgG, at each of the three VAX-24 doses and compared to PCV20, and for the additional four serotypes contained in VAX-24 (and Pneumovax 23), but not in PCV20, the percentage of subjects that experience a four-fold rise in antibody titers. Participants in the study will be evaluated for safety through six months after vaccination.

Additional information about the study can be found at www.clinicaltrials.gov under the identifier NCT05266456.

Anticipated PCV Franchise Milestones

Vaxcyte is advancing the clinical development of its PCV programs with several anticipated key milestones,

VAX-24 Adult Program

VAX-24 Pediatric Program

Conference Call and Webcast

Vaxcyte will hold a webcast and conference call today, Monday, October 24 at 8:00 AM ET to provide topline results from its VAX-24 Phase 1/2 proof-of-concept study. Those who would like

to participate may access the live webcast here, or register in advance for the teleconference here. A live webcast of the conference call will also be available on the investor

relations page of the Vaxcyte corporate website at www.vaxcyte.com. After the live webcast, the event will remain archived on the Vaxcyte website for 30 days.

VAX-24 is an investigational 24-valent PCV candidate designed to prevent IPD, which can be most serious for infants, young children, older adults and those with immune

deficiencies or certain chronic health conditions. The public health community continues to affirm the need for vaccines that offer broader protection to prevent IPD. VAX-24 is intended to improve upon the standard-of-care PCVs for both children and adults by covering the serotypes that are responsible for most of the pneumococcal disease currently in circulation. Vaxcyte aims

to efficiently create and deliver high-fidelity, broad-spectrum vaccines, such as VAX-24, by using modern synthetic techniques, including advanced chemistry and the XpressCFTM cell-free protein synthesis platform. Vaxcyte is deploying this approach with VAX-24 in order to add more pneumococcal strains without compromising the

overall immune response.

In August 2022, the FDA granted Fast Track Designation to VAX-24 for the adult

indication. The Fast Track designation is an FDA process that has been designed to expedite the development and review of drugs, including vaccines, that treat or prevent serious conditions and fill an important unmet medical need.

About Pneumococcal Disease

Pneumococcal disease (PD) is

an infection caused by Streptococcus pneumoniae (pneumococcus) bacteria. It can result in IPD, including meningitis and bacteremia, and non-invasive PD, including pneumonia, otitis media and sinusitis.

In the United States, approximately 900,000 people get pneumococcal pneumonia each year, which is estimated to result in approximately 150,000 hospitalizations and 28,000 deaths. Pneumococci also cause over 50% of all cases of bacterial meningitis

in the United States. Antibiotics are used to treat pneumococcal disease, but some strains of the bacteria have developed resistance to treatments. The morbidity and mortality due to pneumococcal disease are highly significant, particularly for

young children and older adults, underscoring the need for a more broad-spectrum vaccine.

Vaxcyte is a vaccine innovation company engineering high-fidelity vaccines to protect humankind from the consequences of bacterial diseases. The Company is

developing broad-spectrum conjugate and novel protein vaccines to prevent or treat bacterial infectious diseases. Vaxcyte s lead candidate, VAX-24, is a 24-valent,

broad-spectrum pneumococcal conjugate vaccine being developed for the prevention of IPD. Vaxcyte is re-engineering the way highly complex vaccines are made through modern synthetic techniques, including

advanced chemistry and the XpressCFTM cell-free protein synthesis platform, exclusively licensed from Sutro Biopharma, Inc. Unlike conventional cell-based approaches, the Company s

system for producing difficult-to-make proteins and antigens is intended to accelerate its ability to

efficiently create and deliver high-fidelity vaccines with enhanced immunological benefits. Vaxcyte s pipeline also includes VAX-XP, a PCV with

coverage of 31 strains; VAX-A1, a prophylactic vaccine candidate designed to prevent Group A Strep infections; and VAX-PG, a therapeutic vaccine candidate designed to

slow or stop the progression of periodontal disease. Vaxcyte is driven to eradicate or treat invasive bacterial infections, which have serious and costly health consequences when left unchecked. For more information,

visit www.vaxcyte.com.

Forward-Looking Statements

This press release 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 VAX-24, including breadth of coverage, the improvement upon the

standard-of-care; the process and timing of anticipated future development of Vaxcyte s vaccine candidates; the timing and availability of data for the VAX-24 Phase 2 and Phase 3 studies and related regulatory interactions; the timing and submission of an IND application for the VAX-24 Phase 2 infant study and the

availability of Phase 2 topline results; the timing and submission of an IND application for the VAX-XP adult program and the timing and availability of the Phase 1/2 topline data for such program; the demand

for Vaxcyte s vaccine candidates; and other statements that are not historical fact. The words anticipate, believe, could, expect, intend, potential, should,

would and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) convey uncertainty of future events or outcomes and are intended to identify forward-looking statements,

although not all forward-looking statements contain these identifying words. These forward-looking statements are based on Vaxcyte s current expectations and actual results and timing of events could differ materially from those anticipated in

such forward-looking statements as a result of risks and uncertainties, including, without limitation, risks related to Vaxcyte s product development programs, including development timelines, success and timing of chemistry, manufacturing and

controls and related manufacturing activities, potential delays or inability to obtain and maintain required regulatory approvals for its vaccine candidates, and the risks and uncertainties inherent with preclinical and clinical development

processes; the success, cost and timing of all development activities and clinical trials; impacts of COVID-19; and sufficiency of cash and other funding to support Vaxcyte s development programs and

other operating expenses. These and other risks are described more fully in Vaxcyte s filings with the Securities and Exchange Commission (SEC), including, without limitation, its Quarterly Report on Form

10-Q filed with the SEC on August 8, 2022 or in other documents Vaxcyte subsequently files with or furnishes to the SEC. All forward-looking statements contained in this press release speak only as of the

date on which they were made and are based on management s assumptions and estimates as of such date, and readers should not rely upon the information in this press release as current or accurate after its publication date. Vaxcyte undertakes

no duty or obligation to update any forward-looking statements contained in this release as a result of new information, future events or changes in its expectations

(1) Lower bound of the

2-sided 95% confidence interval of the OPA geometric mean titer ratio is greater than 0.5.

(2) Lower bound of the 2-sided 95% confidence interval of the difference in the proportions of participants with a

4-fold increase from Day 1 to Day 29 is greater than 10%, and lower bound of the 2-sided 95% confidence interval of the OPA geometric mean titer ratio is greater

Andrew Guggenhime, President

and Chief Financial Officer

Janet Graesser, Vice President, Corporate Communications and Investor Relations