Key Points

• Increase in bronchiolitis cases since week S13 in the OSCOUR® network and week S14 in the Mayotte sentinel physician network

• Transition to epidemic phase in Week 17 of 2021

  • 102 emergency department visits recorded since Week 17, representing 22% of activity among children under 2 years of age, with an average of 40% of hospitalizations resulting from these visits during this period

  • 41 RSV (Respiratory Syncytial Virus) cases detected through virological surveillance

• Late onset of the epidemic (two to three months later) compared to previous seasons

• Specific context of SARS-CoV-2 circulation leading to stricter enforcement of preventive measures and potential viral competition between SARS-CoV-2 and the bronchiolitis virus