NCT04491877

Study of an Live-Attenuated Respiratory Syncytial Virus Vaccine in Infants and Toddlers

Safety, Immunogenicity, Infectivity, and Dose-Finding Study of an Investigational Live-Attenuated Respiratory Syncytial Virus (RSV) Vaccine in Infants and Toddlers

• Status: Completed
• Phase: Phase 1 / Phase 2
• Study type: Interventional
• Enrollment: 259 (actual)
• Sponsor: Sanofi Pasteur, a Sanofi Company · Industry
• Sex: All
• Age: 6 Months – 18 Months
• Healthy volunteers: Accepted

Summary

The primary objectives of the study were: * To assess the safety profile of each dose of the study product after each and any administration in all infants and toddlers regardless of baseline serostatus. * To characterize the Respiratory Syncytial Virus (RSV) A serum neutralizing antibody responses to the study product in each vaccine group after vaccination in RSV-naïve participants. The secondary objectives of the study were: * To quantify the amount of vaccine virus shed by each participant by baseline serostatus. * To determine the proportion of vaccinated infants and toddlers in each vaccine group infected with the vaccine virus at D56 (56 days after vaccination 1) for Cohorts 1, 2, 3 and 4, and at Day 84 (28 days after vaccination 2) for Cohorts 2 and 4 by baseline serostatus. * To characterize the RSV A serum neutralizing antibody responses to the study product in each vaccine group after vaccination in RSV-experienced participants. * To characterize serum RSV anti-F immunoglobulin G (IgG) antibody responses to the study product in each vaccine group after vaccination by baseline serostatus. * To characterize serum RSV antibody responses (RSV A-neutralizing and anti-RSV F IgG) to the study product in each vaccine group after the RSV surveillance season or at least 5 months after the last vaccine administration by baseline serostatus.

Detailed description

Study duration per participant was maximum 12 months

Conditions

• Respiratory Syncytial Virus Infection

Interventions

Type	Name	Description
BIOLOGICAL	RSV vaccine formulation 1	Pharmaceutical form: Suspension of virus Route of administration: Intranasal
BIOLOGICAL	RSV vaccine formulation 2	Pharmaceutical form: Suspension of virus Route of administration: Intranasal
BIOLOGICAL	Placebo	Pharmaceutical form: Suspension Route of administration: Intranasal

Timeline

• Start date: 2020-09-17
• Primary completion: 2023-04-13
• Completion: 2023-04-13
• First posted: 2020-07-29
• Last updated: 2025-09-09
• Results posted: 2024-06-13

Locations

29 sites across 3 countries: United States, Chile, Honduras

Regulatory

• FDA-regulated drug study