What is the mRNA influenza vaccine study trying to find out?

This study is evaluating the safety and immune response triggered by several mRNA-based flu vaccines compared to licensed vaccines in healthy adults. The research aims to understand how these vaccines work to protect against the flu virus. Pfizer is leading this study to help improve influenza prevention options.

Who may be eligible for this healthy adult clinical trial?

Adults aged 18 years or older who are healthy and medically stable may be eligible. Participants should not have tested positive for influenza, received any flu vaccine, or taken antiviral flu medicine in the past 5 months. This study is open to all genders. Please review eligibility criteria for more details.

Is there any cost to participate in this healthy adult clinical trial?

Study-related care, including the study vaccine and all trial visits, is provided at no cost. However, personal travel expenses to and from the study site may vary and are not guaranteed to be covered. Participants can plan accordingly for any travel needs.

Actively Recruiting

Phase 2

Age: 18Years +

All Genders

Healthy Volunteers

ID07431853

A Phase 2 Randomized, Double-Blind Study Evaluating Safety, Tolerability, and Immune Response of mRNA Influenza Vaccines in Adults 18 and Older

Led by Pfizer · Updated on 2026-05-06

770

Participants Needed

Research Sites

N/A

Total Duration

AI-Summary

What this Trial Is About

Researchers are evaluating the safety and immune response of several mRNA-based influenza vaccines in healthy adults aged 18 years and older. This Phase 2, randomized, double-blind study compares six investigational mRNA flu vaccines against licensed influenza vaccines. The goal is to understand how well these vaccines stimulate the bodys defense against the flu virus and to monitor any side effects. Participants will receive one single dose of either one of the six mRNA influenza vaccine candidates or one of the licensed flu vaccines by intramuscular injection on Day 1. The study includes one treatment period where the vaccines are administered, and the participants will be monitored for reactions and immune responses over time. Participants will visit the study site at least three times over approximately six months. At each visit, blood samples will be collected to measure antibody levels, and a nasal swab will be taken at the first visit. Researchers will track local and systemic reactions within 7 days of vaccination, as well as adverse events, serious adverse events, and any new chronic medical conditions for up to six months. The study aims to assess the immune response and safety profile of the vaccines during this period.

CONDITIONS

Brief Title

A Study to Learn About mRNA Vaccines Against Influenza in Adults

Who Can Participate

Age: 18Years +

All Genders

Healthy Volunteers

Eligibility Criteria

You may qualify if you...

Healthy and medically stable adults aged 18 years or older
Eligible based on medical history, physical exam if required, and investigator judgment

You will not qualify if you...

Tested positive for influenza within 5 months prior to study start
Received any investigational or licensed influenza vaccine within 5 months prior to study start
Taken antiviral treatments for influenza, such as Tamiflu, within 5 months prior to study start

Research Team

Pfizer CT.gov Call Center

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