Invasive Group A Streptococcus infection: epidemiological update as of January 29, 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 29 (the end of week 04).

Key Points as of January 29, 2023

  • 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. Of 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 ARI 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.

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.