NCT07365826

A Clinical Study to Evaluate the Safety, Tolerability, and Immunogenicity of VAX-31 With Influenza Vaccine in Adults ≥ 50 Years of Age

A Phase 3, Randomized, Double-Blind, Placebo-Controlled Clinical Study to Evaluate the Safety, Tolerability, and Immunogenicity of VAX-31 Concomitantly Administered With Seasonal Influenza Vaccine in Healthy Subjects 50 Years of Age and Older

• Status: Active Not Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 1,390 (actual)
• Sponsor: Vaxcyte, Inc. · Industry
• Sex: All
• Age: 50 Years
• Healthy volunteers: Accepted

Summary

This is a Phase 3, randomized, double-blind study to evaluate the safety and immunogenicity of VAX-31 and seasonal influenza vaccine in pneumococcal-naïve adults ≥ 50 years when the two vaccines are administered at the same visit or separately.

Conditions

• Pneumococcal Vaccines

Interventions

Type	Name	Description
BIOLOGICAL	31-valent pneumococcal conjugate vaccine	0.5 mL of VAX-31 will be administered into the deltoid muscle
BIOLOGICAL	Seasonal Influenza Vaccine (SIV) (Flublok)	0.5 mL of SIV into the deltoid muscle
BIOLOGICAL	Placebo	0.5mL of placebo (normal saline) into the deltoid muscle

Timeline

• Start date: 2026-01-12
• Primary completion: 2027-03-01
• Completion: 2027-03-01
• First posted: 2026-01-26
• Last updated: 2026-03-31

Locations

25 sites across 1 country: United States

Regulatory

• FDA-regulated drug study