Effects of coronavirus disease 2019 on the spread of respiratory-transmitted human-to-human bacteria

The coronavirus disease 2019 (COVID-19) pandemic has necessitated significant changes in medical systems, social behaviours, and non-pharmaceutical interventions (NPIs). We aimed to determine the effect of the COVID-19 pandemic on changes in the epidemiology of respiratory-transmitted bacteria that have been unexplored. We utilised a comprehensive national surveillance database from 2018 to 2021 to compare monthly number of patients with four respiratory-transmitted human-to-human bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pyogenes) before and after the COVID-19 pandemic, stratified by specimen sources and age groups. The incidence of detected patients with S. pneumoniae, H. influenzae, and S. pyogenes from both respiratory and blood cultures significantly decreased from 2019 to 2020. In 2021, the incidence of detected patients with the respiratory-transmitted bacterial species, except for S. pyogenes, from respiratory cultures, increased again from April to July, primarily affecting the 0–4-year age group. Our comprehensive national surveillance data analysis demonstrates the dynamic changes and effects of NPIs on respiratory-transmitted bacteria during the COVID-19 pandemic, with variations observed among species, specimen sources, and age groups. •The National AMR and COVID-19 surveillance databases were concurrently utilised.•Data from millions of patients tested for bacterial cultures across Japan were analysed.•Patients with respiratory-transmitted bacteria decreased during the COVID-19 pandemic.•The variation in the decrease among species and specimen sources was demonstrated.•Effect of non-pharmaceutical intervention on respiratory-transmitted bacteria was studied.