Respiratory syncytial virus (RSV) circulation is showing signs of return to pre-pandemic seasonality in the U.S. after two years of irregular onsets and peaks, the Centers for Disease Control and Prevention (CDC) said on Thursday.

The frontrunners in a crowded race to develop the first respiratory syncytial virus vaccine – Pfizer Inc and GSK – will face scrutiny from a panel of experts to the U.S. Food and Drug Administration this week.