CompletedPhase 3

A Study of mRNA-1345 Vaccine Targeting Respiratory Syncytial Virus (RSV) in Adults ≥50 Years of Age

United States3,317 participantsStarted 2022-04-01

Plain-language summary

The main purposes of Part A of this study are to evaluate the safety, tolerability, and immunogenicity of mRNA-1345 coadministered with a seasonal influenza vaccine (Afluria® Quadrivalent); to evaluate the impact of coadministered influenza vaccine on the immune response to RSV-A; and to evaluate the impact of coadministered RSV vaccine on the immune response to influenza. The main purposes of Part B of this study are to evaluate the safety, tolerability, and immunogenicity of mRNA-1345 coadministered with mRNA-1273.214; to evaluate the effect of coadministered mRNA-1273.214 on the immune response to RSV-A; and to evaluate the effect of coadministered RSV vaccine on the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The main purposes of Part C (single arm, open-label) of this study are to evaluate the safety and tolerability of a booster dose (BD) of mRNA-1345 administered at 1 Year following a primary dose; to evaluate the immune response to RSV-A of a BD of mRNA 1345 administered at 1 Year following a primary dose; and to evaluate the immune response to RSV-B of a BD of mRNA-1345 administered at 1 Year following a primary dose.

Who can participate

Age range

50 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Key Inclusion Criteria: Parts A and B both: * Adults ≥50 years of age on the day of the Randomization Visit (Day 1) who are primarily responsible for self-care and activities of daily living. Participants may have one or more chronic medical diagnoses, but should be medically stable as assessed by: Absence of changes in medical therapy within 1 month due to treatment failure or toxicity; Absence of medical events qualifying as SAEs within 1 month of the planned vaccination on Day 1; and absence of known, current, and life-limiting diagnoses which, in the opinion of the investigator, would make completion of the protocol unlikely. * Able to comply with study requirements, including access to transportation for study visits. Part B only: * Fully vaccinated for COVID-19 with an approved primary series according to the locally authorized or approved regimen. If the most recent COVID-19 vaccine was part of a primary series, it must be ≥ 150 days before (or less per local guidance) Day 1. If the most recent COVID-19 vaccine was a booster dose, it must be ≥ 120 days before (or less per local guidance) Day 1. Part C: * Participants at Part C study sites who have been enrolled in Part B (Groups 4 and 5) of this study; have immunogenicity blood sampling at Part B baseline and Day 29; completed the Day 211/end-of-study visits for Part B; were included in the per-protocol (PP) set; and received 1 dose of mRNA-1345 at least 12 months (but no later than 15 months) prior to the time o…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Part A: Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs) Within 7 Days After Day 1 Injection

Timeframe: Within 7 days after Day 1 injection

Part A: Number of Participants With Unsolicited Adverse Events (AEs) After Day 1 Injection

Timeframe: Day 1 through Day 28 (28 days after Day 1 injection)

Part A: Number of Participants With Medically Attended AEs (MAAEs), SAEs, Adverse Events of Special Interest (AESIs), and AEs Leading to Withdrawal

Timeframe: Day 1 through Day 181 (end of Study Part A)

Part A: Geometric Mean Titer (GMT) of Serum Respiratory Syncytial Virus Subtype A (RSV-A) Neutralizing Antibodies (NAbs) at Day 29

Timeframe: Day 29

Part A: Percentage of Participants With Seroresponse in RSV-A NAbs at Day 29

Timeframe: Day 29

Part A: GMT of Serum Anti-hemagglutination (HA) Ab Level, as Measured by Hemagglutination Inhibition (HAI) Assay for Influenza at Day 29

Timeframe: Day 29

Trial details

NCT IDNCT05330975

SponsorModernaTX, Inc.

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2024-11-08

Results submitted2025-11-07

View on ClinicalTrials.gov More Respiratory Syncytial Virus trials

Plain-language summary

Who can participate

Age range

50 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

What they're measuring

Part A: Number of Participants With Solicited Local and Systemic Adverse Reactions (ARs) Within 7 Days After Day 1 Injection

Timeframe: Within 7 days after Day 1 injection

Part A: Number of Participants With Unsolicited Adverse Events (AEs) After Day 1 Injection

Timeframe: Day 1 through Day 28 (28 days after Day 1 injection)

Part A: Number of Participants With Medically Attended AEs (MAAEs), SAEs, Adverse Events of Special Interest (AESIs), and AEs Leading to Withdrawal

Timeframe: Day 1 through Day 181 (end of Study Part A)

Part A: Geometric Mean Titer (GMT) of Serum Respiratory Syncytial Virus Subtype A (RSV-A) Neutralizing Antibodies (NAbs) at Day 29

Timeframe: Day 29

Part A: Percentage of Participants With Seroresponse in RSV-A NAbs at Day 29

Timeframe: Day 29

Part A: GMT of Serum Anti-hemagglutination (HA) Ab Level, as Measured by Hemagglutination Inhibition (HAI) Assay for Influenza at Day 29

Timeframe: Day 29