Positive topline results were announced from a phase 3 trial evaluating the efficacy, safety, and immunogenicity of Pfizer’s bivalent respiratory syncytial virus (RSV) vaccine candidate, RSVpreF, for the prevention of lower respiratory tract disease caused by RSV in adults 60 years of age and older.

The RSVpreF vaccine candidate consists of 2 prefusion F proteins selected to optimize protection against RSV A and B. The randomized, double-blind, placebo-controlled RENOIR trial (ClinicalTrials.gov Identifier: NCT05035212) included approximately 37,000 adults 60 years of age and older who received a single dose of RSVpreF. The primary efficacy endpoint was the number of first RSV-associated lower respiratory tract illness (LRTI-RSV) episodes in the first RSV season.

According to interim analysis conducted by an independent external data monitoring committee, RSVpreF demonstrated vaccine efficacy of 66.7% (96.66% CI, 28.8-85.8) for protection against LRTI-RSV defined by 2 or more symptoms, and vaccine efficacy of 85.7% (96.66% CI, 32.0-98.7) for protection against LRTI-RSV defined by 3 or more symptoms. The vaccine was found to be well tolerated with no safety concerns.

Pfizer plans to present results of the interim analysis at a future medical congress and will submit the results for peer-review in a scientific journal. The Company also intends to submit a Biologics License Application with the Food and Drug Administration in the coming months.


Pfizer announces positive top-line data from phase 3 trial of older adults for its bivalent respiratory syncytial virus (RSV) vaccine candidate. News release. Pfizer Inc. Accessed August 25, 2022. https://www.businesswire.com/news/home/20220825005052/en/Pfizer-Announces-Positive-Top-Line-Data-from-Phase-3-Trial-of-Older-Adults-for-its-Bivalent-Respiratory-Syncytial-Virus-RSV-Vaccine-Candidate