Key Points

In Mayotte, flu outbreaks generally occur during the hot and humid season, between December and March.

• Special context for the 2021/2022 flu season:

  • No flu epidemic in 2020/2021: reduced immunity in the general population.

  • Co-circulation of SARS-CoV-2 with possible viral competition. The third wave of SARS-CoV-2 in Mayotte coincides with a decline in influenza surveillance indicators.

• This year, the 2021–2022 epidemic season is characterized by the occurrence of two epidemics a few weeks apart:

  • An early first epidemic with viral circulation of the A(H3N2) subtype, biologically confirmed as early as week 32 of 2021, and an epidemic phase lasting from week 41 to week 52 of 2021.

  • A second epidemic (Week 12-2022 to Week 20-2022) with viral circulation of the A(H1N1) subtype initially, followed by the B subtype starting in Week 18-2022.

  • A total of 17 severe cases were hospitalized in intensive care, including one death in week 46 of 2021.