Fluctuations in influenza virus and respiratory syncytial virus infections in children before, during and after the COVID-19 pandemic

Following the outbreak of coronavirus disease 2019 (COVID-19) in late 2019, China adopted a range of non-pharmaceutical intervention (NPI) measures, such as lockdowns, social distancing, mask use and case isolation from January 2020 to December 2022. These NPI measures effectively blocked the chain of transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and other respiratory-related pathogens [1–4]. Our previous studies found that the numbers of positive cases and rates of multiple pathogens, including Moraxella catarrhalis, Mycoplasma spp.