Burden and seasonality of RSV bronchiolitis in hospitalized children on a French Caribbean island: Practical lessons from a 13-year study.

Epidemiology of respiratory syncytial virus (RSV) bronchiolitis in the tropics is poorly understood, complicating the effective management of RSV epidemics. The main objective was to describe the seasonality of RSV bronchiolitis epidemics and the clinical characteristics of hospitalized infants over a 13-year period on the French Caribbean island of Martinique. Single-center retrospective observational study including infants under 2 years of age hospitalized at the Martinique University Hospital for RSV-positive bronchiolitis from January 2007 to December 2019. One thousand two hundred thirty-tree cases were included. Epidemics occurred during the rainy season, beginning in September, peaking in October/November and ending in December. A distinct biennial seasonality pattern was observed, with alternating years of high and low incidence. Mean duration of epidemics was of 11 weeks. Clinical characteristics of patients were similar to those hospitalized in temperate areas. Median hospital stay was 4 days. Median age was 3 months, 14.1% of patients were born prematurely, 2.5% had congenital heart disease and 41.1% required oxygen therapy. In Martinique, RSV bronchiolitis epidemics in infants occur in a regular biennial pattern during the rainy season. An accurate knowledge of the local seasonality will allow us to better anticipate hospital organization before epidemics.