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

• Stabilization in the number of pediatric cases of severe ARI requiring hospitalization in critical care units since week 49 of 2022. More than half of the cases resulted from a viral infection. Among the 91 cases recorded, 9 have died. Five additional deaths from ARI prior to hospital admission have been reported.

• A decrease in the number of outpatient visits and emergency department visits for non-invasive SGA infections, tonsillitis, and scarlet fever during the second half of December, likely due to school holidays; however, a new increase has already been observed in early January (a period not covered by this report) and is being monitored.

• The current epidemiological situation regarding IISGA 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 has been observed in other European countries, notably in the United Kingdom, where an increase in the number of cases in 2022, a predominance of the emm1 genotype, and a high proportion of co-infections with a respiratory virus have also been noted.

• The resurgence of GAS infections could 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 superinfections of viral respiratory infections.