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# Panel Backs Pfizer’s RSV Vaccine
- URL: https://www.fdaweb.com/panel-backs-pfizers-rsv-vaccine/
- Published: 2023-05-18T12:00:00.000Z
- Updated: 2026-09-14T18:32:49.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5154491

FDA’s Vaccines and Related Biological Products Advisory Committee 5/18 voted 14-0 that a Pfizer BLA demonstrated effectiveness for its Abrysvo (RSVpreF) vaccine for preventing respiratory syncytial virus (RSV) in infants from birth through six months by active immunization of pregnant individuals. A separate vote of 10-4 found that the data supported the safety of the vaccine.

In a [briefing document](https://www.fda.gov/media/168185/download?ref=fdaweb.com) released in advance of the committee meeting, agency reviewers said that vaccine efficacy for preventing severe RSV within 90 days after birth was 81.8%, with six cases in the vaccine group and 33 cases in the placebo group. Vaccine efficacy within 180 days after birth was 69.4%, with 19 cases in the vaccine group and 62 cases in the placebo group. Regarding safety, premature births were reported in 5.7% of infants in the vaccine group compared with 4.7% in the placebo group. Agency reviewers said this was a numerical imbalance and “not statistically significant.”

In voting no on the safety question, Children’s Hospital of Philadelphia professor **Paul Offit** said there were not enough safety data on premature births. “If you’re, in any sense, risking premature births with this vaccine, then I think there will be a big price to pay, and so I guess I just don’t feel we have enough data to be reassured, so that’s why I voted no,” he said after voting.

Scientific advisor and respiratory diseases consultant **Daniel Feikin** said he was concerned about the preterm birth imbalance but he voted yes because he was not convinced that there’s a clear causal relationship. “I’m still struck by the fact that this study was done in the setting of a pandemic … when so many things were different, and that this signal was not seen in high income countries,” he said. “And the key will be doing really good post marketing surveillance.”