In a significant move, the U.S. Food and Drug Administration (FDA) has ordered pharmaceutical giants GSK and Pfizer to include warnings about the risk of Guillain-Barré syndrome (GBS), a rare but potentially paralyzing neurological disorder, on the labels of their respiratory syncytial virus (RSV) vaccines.

The decision, announced on January 7, follows an observational study that identified an increased risk of GBS within 42 days of vaccination. This development comes as RSV activity remains "very high" across the U.S., particularly among young children and older adults, according to the Centers for Disease Control and Prevention (CDC).

The FDA’s mandate affects GSK’s Arexvy and Pfizer’s Abrysvo, both approved in May 2023 for adults aged 60 and older. While the agency maintains that the benefits of these vaccines outweigh the risks, the new warning underscores the need for heightened awareness among healthcare providers and patients about the potential side effects of these and other vaccines.