This study is a Phase III, parallel group, randomized, observer blind, placebo controlled, multi-national, multi-center, multi-arm study to be conducted in 947 healthy children enrolled at 6 months to \<22 months of age. The purpose of the study is 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: -Aged 6 months to \< 22 months on the day of inclusion (means from the day of the 6-month birthday to the day before the 22-month birthday. The second vaccine administration should be administered before the study participant has turned 24 months of age).
* Participants who are healthy as determined by medical evaluation including medical history.
* For Cohort 1 and Cohort 2 (contingent upon satisfactory safety profile of the RSVt vaccine in Cohort 1):
* 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.
* For Cohort 2:
* Participant born at full term of pregnancy (≥ 37 weeks of gestation). Exclusion Criteria: Participants are excluded from the study if any of the following criteria apply:
* Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months).
* Known systemic hypersensitivity to any of the study intervention components, or hi…
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
1
RSV A serum neutralizing antibody titers at 28 days post dose 2 (D85)
Timeframe: Day 85
2
RSV B serum neutralizing antibody titers at 28 days post dose 2 (D85)
Timeframe: Day 85
3
Presence of unsolicited systemic adverse events (AEs) reported in the 30 minutes after each vaccination
Timeframe: Within 30 minutes after each vaccination
4
Presence of solicited administration site reactions within 21 days after each vaccination
Timeframe: Within 21 days after each vaccination
5
Presence of solicited systemic reactions within 21 days after each vaccination
Timeframe: Within 21 days after each vaccination
6
Presence of unsolicited AEs within 28 days after each vaccination
Timeframe: Within 28 days after each vaccination
7
Presence of medically attended adverse events MAAEs throughout the study