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

> **NCT04491877** · PHASE1,PHASE2 · COMPLETED · sponsor: **Sanofi Pasteur, a Sanofi Company** · enrollment: 259 (actual)

## Conditions studied

- Respiratory Syncytial Virus Infection

## Interventions

- **BIOLOGICAL:** RSV vaccine formulation 1
- **BIOLOGICAL:** RSV vaccine formulation 2
- **BIOLOGICAL:** Placebo

## Key facts

- **NCT ID:** NCT04491877
- **Lead sponsor:** Sanofi Pasteur, a Sanofi Company
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE1,PHASE2
- **Study type:** INTERVENTIONAL
- **Status:** COMPLETED
- **Start date:** 2020-09-17
- **Primary completion:** 2023-04-13
- **Final completion:** 2023-04-13
- **Target enrollment:** 259 (ACTUAL)
- **Last updated:** 2025-09-09


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT04491877

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT04491877, "Study of an Live-Attenuated Respiratory Syncytial Virus Vaccine in Infants and Toddlers". Retrieved via AI Analytics 2026-06-25 from https://api.ai-analytics.org/clinical/NCT04491877. Licensed CC0.

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*[Clinical trials dataset](/datasets/clinical-trials) · CC0 1.0*