Group A streptococcal infections, especially those with an invasive course, continue to be a significant medical problem in industrialized countries, and therefore, several presentations at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2023) addressed this topic. Among other things, they provide insight into the infection process in various European countries and currently show an incidence of invasive and non-invasive infections much higher than the figures for the years before the Covid pandemic.
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Data from the United Kingdom (UK) show an increase in the emm1 strain associated with severe forms. While there was a significant decrease in streptococcal transmission, especially among children, in 2020 and 2021 as a result of Covid 19 measures, infections rose again significantly when the measures ended. Both scarlet fever and invasive infections (iGAS) have been affected by this development, with the latter still occurring. In December 2022, an unusually high incidence of both scarlet fever and iGAS was reported. The incidence of scarlet fever is now in the normal range, but iGAS is increasingly occurring around this time of year. A total of 690 cases of iGAS were reported in the UK in 2022, more than double the long-term pre-Covid-19 average. In 2022, there were 60 deaths related to iGAS infection, with a fatality rate (CFR) of 9.2 percent. The number of iGAS-related deaths has also doubled compared to the years prior to the pandemic.
This may be related to a change in the spectrum of germs. For example, the strain emm1, which is most likely to cause an invasive infection, was found more frequently than in the years before Covid-19. emm1 now accounts for 48.8 percent of group A streptococcal infections – compared to 21 percent in the years before Covid-19. At the same time, there was also a social shift in invasive infections. Whereas in the past it was only socially disadvantaged people who were affected by iGAS, now the incidence is highest in the upper middle class, i.e. in the second highest socioeconomic quintile.1
