Delayed Bronchiolitis Epidemic in French Primary Care Setting Driven by Respiratory Syncytial Virus: Preliminary Data from the Oursyn Study, March 2021.

We report early results from a prospective primary care bronchiolitis surveillance study in France in which a 10-week delayed epidemic was detected from February to March 2021. Among 225 children under 2 years with swab testing for a first bronchiolitis episode, 55% had a positive test for RSV, 0 for influenza, and 1 for severe acute respiratory syndrome coronavirus 2.