Invasive Group A Streptococcal Infection (IGAS): Update as of December 20, 2022, and Surveillance System

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 December 18 (end of week 50).

The next update will be published during the first week of January.

Key Points

  • Increase in pediatric cases of severe IISGA hospitalized in critical care units from September 1, 2022, through week 49; the majority of cases (66%) are linked to respiratory infections, with or without toxic shock syndrome. Data from week 50 suggest a decrease but have not yet been finalized. Of the 59 cases recorded, 6 have died. Three additional deaths from IISGA prior to hospital admission have been reported.

  • The incidence of scarlet fever in children continued to rise in week 50, according to emergency department visit data from the Oscour® network. However, in week 50, data on calls to SOS Médecins suggest a trend toward stabilization, though at a level that remains high. Data from outpatient pediatric care, collected by the PARI network, suggest a downward trend in cases of strep throat and scarlet fever in week 50.

  • The current epidemiological situation regarding ARI is not linked to the emergence of a new bacterial strain but primarily to two already known genotypes (emm12 and emm1).

  • The resurgence of ARI could result, at least in part, from a rebound following the lifting of containment measures among children whose immune systems have not been exposed to the strains of ARI that typically circulate. These infections are also frequently secondary infections following viral respiratory infections, which are also on the rise.

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.