Attribution of invasive group A streptococcal infections to varicella and respiratory virus circulation, the Netherlands, 2010-2023

Abstract

AbstractBackgroundAfter the lifting of most COVID-19 control measures, many infectious diseases re-emerged in 2022. A strong increase in invasive group A streptococcal (iGAS) infections, among both adults and young children, was reported by several countries. Viral infections such as influenza and varicella, known risk factors for iGAS infection, also increased during 2022. We estimated the proportion of GAS skin and soft tissue infections (SSTI) in children aged 0-5 years attributable to varicella, and the proportion of GAS pneumonia/sepsis in children aged 0-5 and adults attributable to respiratory viruses in the Netherlands.MethodsWe performed time-series regression using weekly data on influenza A and B, RSV, hMPV and SARS-CoV-2, varicella and non-invasive GAS infections, and GAS isolates cultured from blood, lower airways, skin, pus and wounds, from January 2010 to March 2023.ResultsUp to 2022, approximately 50%(95%CI 36-64%) of GAS SSTI in children were attributable to varicella. Between January 2022 and March 2023, 34%(95%CI 24-43%) of GAS SSTI cases were attributable to varicella. Of iGAS pneumonia/sepsis between January 2022 and March 2023, 25%(95%CI 18-31%) and 37%(95% CI 23-53%) was attributable to respiratory virus infections in adults and children, respectively, with the largest contributor being influenza A.ConclusionsVaricella and respiratory virus infections likely contributed to, but only partly explain, the observed iGAS increase among children and adults in 2022-2023 in the Netherlands. Public health measures to control viral infections, such as vaccination against varicella or influenza, might reduce the iGAS disease burden but will not suffice to curb the current high incidence.