TerminatedPhase 3

A Study on the Immunogenicity and Safety of 3 Different Dose Concentrations of a Respiratory Syncytial Virus Vaccine in Infants and Toddlers

Stopped: Sponsor decision

Honduras42 participantsStarted 2024-11-25

Plain-language summary

This study was a Phase III, parallel group, randomized, observer blind, placebo controlled, multi-national, multi-center, multi-arm study conducted in 42 healthy children enrolled at 6 months to \<22 months of age. The purpose of the study was to evaluate the non-inferiority of the immune response of the lower dose (LD) when compared to the standard dose (SD) respiratory syncytial virus infant and toddler (RSVt) vaccine and the safety of the LD, SD and high dose (HD) vaccine in preterm born children and of the HD vaccine in full term born children administered by intranasal route and compared to placebo.

Who can participate

Age range

6 Months – 21 Months

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.

Inclusion criteria

-Participant born 28 through 36 weeks of gestation and medically stable as assessed by the investigator, based on the following definition: "Medically stable" refers to the condition of premature infants who do not require significant medical support or ongoing management for debilitating disease and who have demonstrated a clinical course of sustained recovery by the time they receive the first dose of study intervention.

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

Cohort 2: Geometric Mean Titers (GMT) of RSV A Serum Neutralizing Antibodies at Day 85 (Post-Dose 2)

Timeframe: Day 85 (28 days post-vaccination 2)

Cohort 2: Geometric Mean Titers of RSV B Serum Neutralizing Antibodies at Day 85 (Post-Dose 2)

Timeframe: Day 85 (28 days post-vaccination 2)

Cohorts 1 and 2: Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)

Timeframe: Up to 30 minutes after each vaccination (post-dose on Day 1)

Cohorts 1 and 2: Number of Participants With Solicited Administration Site Reactions

Timeframe: Up to 21 days after each vaccination (post-dose on Day 1)

Cohorts 1 and 2: Number of Participants With Solicited Systemic Reactions

Timeframe: Up to 21 days after each vaccination (post-dose on Day 1)

Cohorts 1 and 2: Number of Participants With Unsolicited Adverse Events

Timeframe: Up to 28 days after each vaccination (post-dose on Day 1)

Trial details

NCT IDNCT06705140

SponsorSanofi Pasteur, a Sanofi Company

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2025-06-11

Results submitted2026-06-11

View on ClinicalTrials.gov More RSV Immunisation trials