Invasive Group A Streptococcus infection: epidemiological update as of January 1, 2023

Epidemiological update following several pediatric cases of invasive Group A Streptococcus infections, primarily among children under the age of 10 in several regions of France.

During the second half of November 2022, clinicians and pediatric intensive care specialists reported to Santé publique France and the Regional Health Agencies (ARS) a higher-than-usual number of pediatric cases of invasive Group A Streptococcus (IGAS) infections in their departments, some of which were fatal. These reports came from various regions (Occitanie, Auvergne-Rhône-Alpes, Nouvelle-Aquitaine) and primarily involved children under the age of 10.

To objectively assess an increase in cases toward the end of 2022, an initial assessment was conducted on December 8 using nationally available data on Group A Streptococcus infections.

Santé publique France is releasing an update today on trends in key epidemiological indicators based on data as of January 1, 2023 (end of week 52).

Key Points

  • The number of pediatric cases of severe ARI requiring hospitalization in critical care units has stabilized since week 49 of 2022. More than half of the cases were caused by a viral infection. Of the 91 cases reported, 9 resulted in death. Five additional deaths from ARI prior to hospital admission were 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.

Prevention tips to reduce the risk of invasive Group A streptococcal infections

Group A streptococcus (GAS) is a strictly human pathogen transmitted via respiratory droplets and direct contact (nasal secretions, skin lesions, etc.). It most commonly causes mild, non-invasive infections, such as strep throat, impetigo, and scarlet fever. More rarely, it causes serious invasive infections (necrotizing skin infections, puerperal infections, pneumonia and pleuropneumonia, and meningitis) that may be associated with streptococcal toxic shock syndrome (STSS).

To limit the risk of transmission, it is recommended to follow the same preventive measures used against winter viruses:

  • handwashing,

  • wearing a mask for people with respiratory infections,

  • coughing or sneezing into the crook of the elbow.

As a reminder, the High Council for Public Health recommends that a child with scarlet fever or GAS tonsillitis be kept out of school or other group settings (for up to 2 days after starting antibiotic therapy) [8]. A suspected case of non-invasive GAS infection (e.g., strep throat, scarlet fever) should prompt an immediate consultation to confirm the cause so that appropriate treatment can be initiated.

Implementation of Enhanced Surveillance

Active surveillance is being implemented by Santé publique France and the GFRUP (Francophone Group for Pediatric Intensive Care and Emergency Medicine) to supplement the existing surveillance system, better assess the epidemiological situation, and characterize severe cases admitted to intensive care.

This data collection complements the microbiological surveillance of Group A streptococci conducted by the National Reference Center for Streptococci, as well as that of the EPIBAC network. The GAS strains submitted to the NRC by bacteriology laboratories are characterized there, particularly at the genotypic level.