Pfizer's 25-Valent Pediatric Pneumococcal Conjugate Vaccine Candidate Shows Robust Phase 2 Data at IDWeek 2026

NEW YORK--( BUSINESS WIRE)-- Pfizer Inc. (NYSE: PFE) today announced detailed results across serotypes from a Phase 2 study ( NCT06524414) for its investigational 25-valent pneumococcal conjugate vaccine candidate, PF-07872412 (25vPnC), in infants. In the study, a four-dose series of 25vPnC elicited robust immune responses against all 25 serotypes and showed safety and tolerability comparable to four doses of PREVNAR 20 ® (Pneumococcal 20-valent Conjugate Vaccine). These findings were shared today in an oral presentation at IDWeek 2026 in Washington, D.C. 1

These data support the ongoing Phase 3 development program for 25vPnC, which, if successful, could help provide protection against serotypes collectively responsible for approximately 84% of invasive pneumococcal disease (IPD) cases among children under five years of age in the U.S. 2

“These encouraging data build on more than 25 years of progress in protecting children from serious pneumococcal disease with PREVNAR vaccines. By expanding serotype coverage and applying next-generation technology to the historically challenging serotype 3, this candidate aims to extend the substantial reductions in disease that existing vaccines have achieved. If successful, it could help provide children with the broadest protection against invasive pneumococcal disease to date.”

— Annaliesa Anderson, Ph.D., Senior Vice President and Chief Vaccines Officer, Pfizer

Phase 2 Study Results Across 25 Serotypes

The Phase 2 study is evaluating the safety, tolerability, and immunogenicity of the 25-valent vaccine candidate (25vPnC) compared with PREVNAR 20 in healthy infants. These data build on results announced earlier this year showing:

Detailed results from the presentation can be found online here.

Continuing Pfizer’s Commitment to Pneumococcal Disease Prevention

These results build on Pfizer’s long-standing commitment to protecting people from pneumococcal disease. Pfizer is advancing two next-generation pneumococcal conjugate vaccine candidates across pediatric and adult populations.

For more information on Pfizer’s Commitment to Vaccines, please visit: Vaccines | Pfizer | Pfizer. More information on Pfizer’s overall presence at IDWeek 2026 is here.

U.S. INDICATION AND IMPORTANT SAFETY INFORMATION FOR PREVNAR 20

INDICATION

PREVNAR 20 is a vaccine approved for:

The indication for the prevention of pneumonia caused by S. pneumoniae serotypes 8, 10A, 11A, 12F, 15B, 22F, and 33F in individuals 18 years of age and older is approved based on immune responses. Continued approval may depend on a supportive study.

IMPORTANT SAFETY INFORMATION

Please click for PREVNAR 20 Full Prescribing Information.

About Pfizer: Breakthroughs That Change Patients’ Lives

At Pfizer, we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality, safety and value in the discovery, development and manufacture of health care products, including innovative medicines and vaccines. Every day, Pfizer colleagues work across developed and emerging markets to advance wellness, prevention, treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world's premier innovative biopharmaceutical companies, we collaborate with health care providers, governments and local communities to support and expand access to reliable, affordable health care around the world. For more than 175 years, we have worked to make a difference for all who rely on us. We routinely post information that may be important to investors on our website at www.Pfizer.com. In addition, to learn more, please visit us on www.Pfizer.com and follow us on X at @Pfizer and @Pfizer_News, LinkedIn, YouTube and like us on Facebook at www.facebook.com/Pfizer/.

Disclosure Notice

The information contained in this release is as of October 24, 2026. Pfizer assumes no obligation to update forward-looking statements contained in this release as the result of new information or future events or developments.

This release contains forward-looking information about an investigational pediatric 25-valent pneumococcal conjugate vaccine candidate PF-07872412 (25vPnC) and an investigational adult fifth-generation, 35-valent vaccine candidate vaccine candidate (35vPnC), including their potential benefits, results from a Phase 2 study of 25vPvC in infants and clinical development plans and timing for 25vPnC and 35vPnC, that involves substantial risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements. Risks and uncertainties include, among other things, the uncertainties inherent in research and development, including the ability to meet anticipated clinical endpoints, commencement and/or completion dates for our clinical trials, regulatory submission dates, regulatory approval dates and/or launch dates, as well as the possibility of unfavorable new clinical data and further analyses of existing clinical data; risks associated with initial, preliminary or interim data; the risk that clinical trial data are subject to differing interpretations and assessments by regulatory authorities; whether regulatory authorities will be satisfied with the design of and results from our clinical studies; whether and when applications may be filed in any jurisdictions for 25vPnC or 35vPnC; whether and when any such applications may be approved by regulatory authorities, which will depend on myriad factors, including making a determination as to whether the product’s benefits outweigh its known risks and determination of the product’s efficacy and, if approved, whether 25vPnC and 35vPnC will be commercially successful; decisions by regulatory authorities impacting labeling, manufacturing processes, safety and/or other matters that could affect the availability or commercial potential of 25vPnC and 35vPnC; uncertainties regarding the ability to obtain or maintain recommendations from vaccine advisory or technical committees and other public health authorities and uncertainties regarding the commercial impact of any such recommendations; risks and uncertainties related to changes to vaccine or other healthcare policy in the U.S.; challenges related to public vaccine confidence or awareness; risks and uncertainties related to issued or future executive orders or other new, or changes in, laws or regulations; uncertainties regarding the impact of COVID-19 on Pfizer’s business, operations and financial results; and competitive developments.

A further description of risks and uncertainties can be found in Pfizer’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025 and in its subsequent reports on Form 10-Q, including in the sections thereof captioned “Risk Factors” and “Forward-Looking Information and Factors That May Affect Future Results”, as well as in its subsequent reports on Form 8-K, all of which are filed with the U.S. Securities and Exchange Commission and available at www.sec.gov and www.pfizer.com.

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