After an epidemic surge in 2022, group A streptococcal infections, responsible in particular for scarlet fever, have decreased sharply, remaining more frequent than before Covid but less severe than in 2022-2023, according to a report by Public Health France published on Monday.
Group A streptococci are a class of bacteria that cause a variety of infections, generally mild, which frequently result in tonsillitis. They are notably responsible for scarlet fever, one of the main childhood illnesses.
More rarely, they can cause serious invasive infections (invasive group A streptococcal infections – IAGSI) such as septicemia. These bacteria are transmitted through respiratory droplets and direct contact (nasal secretions, skin lesions, etc.).
In 2022-2023, the number of infections, and in particular of serious invasive infections, had increased sharply, in connection with "the lifting of barrier measures" in force during the Covid-19 pandemic, and the emergence of a more dangerous strain (M1UK), this study observes.
The study relies on several indicators including data on emergency room visits, outpatient consultations at SOS doctors, the incidence of IISGA or the proportion of death certificates mentioning an IIGSA.
Since the end of 2024, the number of outpatient consultations and emergency room visits for scarlet fever has "returned to levels observed during seasons prior to the COVID-19 epidemic", notes Public Health France (SpF).
The incidence rate of invasive infections, which peaked at 6.2 per 100,000 inhabitants in 2023, fell to 4.5 in 2024 but remains "higher than that usually reported" before Covid-19. Data from the first half of 2025 "suggest a continuation of this trend."
The severity of infections "appears to have decreased significantly" compared to 2022-2023, returning to a level "comparable to the pre-Covid period" indicates SpF, which observes "a decrease in the frequency" of streptococcal shock syndromes, as well as in the number of death certificates linked to these infections.
"This decrease in the most severe IISGA is particularly visible in children," the study specifies.
The data also show "a significant decrease" in the circulation of the M1UK strain in 2024 and early 2025.
Unlike childhood illnesses of viral origin such as bronchiolitis, group A streptococcal infections can be treated with antibiotics, such as amoxicillin or penicillin.
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