PURPOSE: Since winter 2022, invasive GAS (iGAS) infections have re-emerged in Europe, causing severe diseases in children and adults. We aimed to examine whether this reported post-pandemic increase was associated with an increased disease severity and/or a shift in clinical disease phenotypes.

METHODS: We performed detailed clinical phenotyping of patients hospitalized with iGAS infections at a 1410-bed tertiary German Medical Center from 01/2015 to 09/2023.

RESULTS: One hundred seventy-eight patients were included: 50 children (28.1%) and 128 adults (71.9%). IGAS infections of Q1/2023 exceeded the pre-pandemic average by 551% (1200% for children). The mean age of affected patients shifted significantly post-pandemically (49.5 ± 26.5 to 32.4 ± 28.2 years of age, p < 0.05), mainly due to the higher percentage of children affected with iGAS infections (15.2% pre-pandemic, 44.2% post-pandemic). CFR was significantly lower for children (2%) compared to adults (11.7%) (p < 0.05) and decreased from 13% to 6.5% post-pandemically (p = 0.148). Duration of antibiotic therapy (13.5 (10 to 21) to 10 (9 to 14) days), length of hospital (10 (4 to 25) to 7 (5 to 15) days), and ICU stay (7.0 (2.5 to 18.0) to 5.0 (3.0 to 8.5) days) were shorter post-pandemically. Despite the higher post-pandemic percentage of affected children, PICU admissions (57% before to 32% after), use of catecholamines (28.6% to 11.8%), invasive ventilation (35.7% to 17.6%) and CFR (7% to 0%) were all lower after the pandemic.

CONCLUSION: Children were at higher risk for iGAS infections post-pandemically. The surge of post-pandemic iGAS infections was not accompanied by increased iGAS-associated morbidity and mortality.