The following is from The Vaccine Reaction.

On June 8, 2023, the U.S. Food and Drug Administration’s (FDA) Antimicrobial Drugs Advisory Committee (AMDAC) voted unanimously (21-0) in favor of AstraZeneca and Sanofi’s new nirsevimab (Beyfortus) monoclonal antibody drug believed to provide protection for infants from respiratory syncytial virus (RSV) disease and other lower respiratory tract infections during their first year of life.

The path to pharmaceutical RSV protection spans several decades, with clinical trials for an RSV vaccine ending abruptly in the 1960s after the shot unexpectedly sickened and hospitalized 80 percent of children in the trial.

The inactivated virus used in the shot exacerbated the disease once trial participants caught RSV naturally, leading to two children’s deaths and researchers going back to the drawing board.

Today, more than 60 years later, 12 infants have died during clinical trials of the new nirsevimab, two from “unknown causes” thought to be linked to sudden infant death syndrome (SIDS).