Bordetella pertussis, Chlamydia pneumoniae, and Mycoplasma pneumoniae Findings in Children During COVID-19 Pandemic in Finland

Social restrictions effectively interrupted the typical respiratory virus circulation. The aim of this report is to describe how atypical pneumonia bacteria detections have changed during the COVID-19 pandemic in Finnish children. Bordetella pertussis, Chlamydia pneumoniae, and Mycoplasma pneumoniae findings were gathered from the National Infectious Diseases Register from 2015 to 2021 and stratified into three age groups (0–4, 5–9, and 10–14 years). Incidences per 100,000 children were calculated and 2020 and 2021 was compared to the mean incidence of reference years (2015–2019) by incidence rate ratios. B. pertussis incidence was 32% lower in 2020 and 88% lower in 2021 compared to reference years. C. pneumoniae detections decreased rapidly in 2020 and not a single detection of C. pneumoniae was reported to the register in 2021. M. pneumoniae incidence was 72% lower in 2020 and 89% lower in 2021 than in the reference years. All these findings were seen in all age groups. As the incidences of B. pertussis, C. pneumoniae, and M. pneumoniae detections have been low throughout the pandemic, it seems that the social restrictions have been effective in preventing the spreading of these respiratory bacteria in children. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42399-022-01251-9.