Following the alert issued during the second half of November 2022 regarding a higher-than-usual number of pediatric cases of IISGA, an initial assessment was conducted on December 8 based on available data and published on the Santé publique France website. In addition, active surveillance was immediately implemented by Santé publique France and the GFRUP (Francophone Group for Pediatric Intensive Care and Emergency Medicine) to strengthen the existing surveillance system, better assess the epidemiological situation, and characterize severe cases admitted to critical care units. We provide an update based on data as of January 1, 2023 (end of week 52) on the trends in key epidemiological indicators.

Key Points

• A decrease in the number of pediatric cases of severe IISGA hospitalized in critical care units has been observed since week 51 of 2022. More than half of the cases occurred following a viral infection. Among the 121 cases recorded (+30 cases compared to the 91 cases reported in the last epidemiological update on January 1, 2023), 11 have died. Six additional deaths from severe acute respiratory infections prior to hospital admission have been reported.

• A new increase in the number of outpatient visits and emergency room visits for non-invasive SGA infections, tonsillitis, and scarlet fever has been observed since early January 2023, following a decrease noted during the two weeks of school holidays in late December.

• The current epidemiological situation regarding ARI is not linked to the emergence of a new bacterial strain but possibly to an increase in the frequency of the already known emm1 genotype.

• The increase in the number of cases among adults, suggested by CNR data, will need to be confirmed by additional analyses (analysis of Epibac and PMSI data).

• A similar situation is observed in other European countries, notably in the United Kingdom, where a high incidence affects all age groups and particularly those under 10 years of age. The United Kingdom and the Netherlands also report an increase in cases among adults in recent weeks.

• The resurgence of GAS infections may result, at least in part, from a post-restriction rebound among children whose immune systems have not been exposed to the GAS strains that typically circulate. These infections are also frequently secondary infections following viral respiratory infections.