A Study to Learn About How the Flu and COVID-19 Vaccines Act in Healthy People

A PHASE 1/2 RANDOMIZED, DOUBLE-BLINDED STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF MODIFIED RNA VACCINE CANDIDATES AGAINST INFLUENZA AND COVID-19 IN HEALTHY INDIVIDUALS

Status

Completed

Phases

Phase 1Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT06821061

Enrollment

2650

Registered

2025-02-11

Start date

2025-02-10

Completion date

2025-12-17

Last updated

2026-01-26

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

COVID-19 (Coronavirus Disease 2019), Influenza

Brief summary

The purpose of this study is to learn about how the flu and COVID vaccines act when given alone or when mixed together. This study is seeking healthy participants aged 18 or older. All participants in this study will receive only 1 shot to their arm, either a flu or COVID vaccine, alone or mixed. Participants will take part in this study for about 6 months, and participants will need to visit the clinical study site at least 4 times.

Interventions

BIOLOGICALInvestigational Influenza Vaccine

Investigational Influenza Vaccine

BIOLOGICALInvestigational COVID-19 Vaccine

Investigational COVID-19 Vaccine

COMBINATION_PRODUCTInvestigational Influenza and COVID-19 Combination Vaccine

Investigational Combined Influenza and COVID-19 Vaccine

BIOLOGICALLicensed Influenza Vaccine 1

Licensed Influenza Vaccine 1

BIOLOGICALLicensed Influenza Vaccine 2

Licensed Influenza Vaccine 2

BIOLOGICALLicensed Influenza Vaccine 3

Licensed Influenza Vaccine 3

BIOLOGICALLicensed COVID-19 Vaccine

Pfizer-BioNTech COVID-19 Vaccine

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Yes

Inclusion criteria

* Participants 18 years of age or older * Healthy participants who are determined by medical history, physical examination (if clinically required), and clinical judgement of the investigator to be eligible for inclusion in the study

Exclusion criteria

* Vaccination with any investigational or licensed influenza vaccine within 150 days of enrollment * Vaccination with any investigational or licensed COVID 19 vaccine within 150 days of enrollment. * Receipt of antiviral therapies for influenza (eg, Tamiflu) within 180 days prior to Day 1. Refer to the study contact for further eligibility details

Design outcomes

Primary

Measure	Time frame
Percentage of participants reporting prompted local reactions within 7 days following investigational product administration	Day 7
Percentage of participants reporting prompted systemic events within 7 days following investigational product administration	Day 7
Percentage of participants reporting adverse events (AEs) through 1 month following investigational product administration	1 month
Percentage of participants reporting serious adverse events (SAEs) through 6 months following investigational product administration	6 months

Secondary

Measure	Time frame
GMTs before and through 1 month following investigational product administration	Before vaccination through to 1 month after vaccination

Countries

United States

Contacts

STUDY_DIRECTORPfizer CT.gov Call Center

Pfizer

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026