New Pneumococcal Vaccine Shows Promise in Phase 3 Trial

A new vaccine candidate for adults over 50 demonstrated broad serotype coverage in recent clinical trial results.

Updated on Oct. 30, 2026 in COVID-19

A clear medical vial sits on a sterile laboratory workbench, highlighting the research efforts behind a new pneumococcal vaccine. — Vaxcyte reported positive phase 3 results for its VAX-31 pneumococcal vaccine candidate on October 5, 2026, aimed at improving protection for adults aged 50 and older. AI Illustration. Upload story photo >

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Vaxcyte reported positive phase 3 results for its VAX-31 pneumococcal vaccine candidate on October 5, 2026. The clinical trials enrolled 6,189 adults aged 50 and older to evaluate the vaccine's ability to protect against invasive pneumococcal disease and pneumonia.

Why it matters

Current adult pneumococcal vaccines do not cover all disease-causing serotypes, leaving some individuals at continued risk. This trial result is a significant step toward broadening protection against the bacteria responsible for these serious respiratory conditions.

In a pivotal phase 3 trial involving 6,189 adults, VAX-31 met all primary immunogenicity endpoints compared to existing vaccines. Findings from this trial, which remains in the clinical stage, demonstrated noninferiority for 28 shared serotypes and superiority for four additional serotypes.

The players

Vaxcyte

A biotechnology company focused on developing novel vaccines to prevent infectious diseases.

The details

VAX-31 utilizes a site-specific conjugation technology to expand the number of serotypes included in the vaccine while maintaining a robust antibody response. By targeting 31 serotypes, the vaccine aims to improve coverage against invasive pneumococcal disease and pneumonia compared to current standards. The study observed no serious vaccine-related adverse events among the participants.

October 5, 2026: Topline results from the phase 3 OPUS-1 trial were released.
October 21-24, 2026: Study design details were presented at the IDWeek 2026 conference in Washington, DC.
First half of 2027: Results are expected from the remaining OPUS-2 and OPUS-3 trials.
First half of 2028: Vaxcyte plans to submit a Biologics License Application.

Health Landscape

Pneumococcal vaccination strategies have historically centered on increasing serotype coverage to keep pace with evolving bacterial strains. VAX-31 represents a move toward higher-valency solutions in the pipeline, building on the established success of previous conjugate vaccine generations.

This development indicates a potential future option for broader pneumococcal protection for adults over 50. You should continue to discuss your current vaccination schedule and eligibility for existing pneumococcal vaccines with your physician.

The takeaway

This candidate vaccine shows promise for covering more strains of bacteria than current options. Continue to follow professional guidance on existing pneumococcal vaccines, which remain an essential tool for preventing respiratory illness in older adults.

What happens next

Results from the OPUS-2 and OPUS-3 trials are expected in the first half of 2027, followed by a planned Biologics License Application submission in the first half of 2028.