Nonpharmaceutical interventions effectively reduced influenza spread during the COVID-19 pandemic

Seasonal infl uenza, which is transmitted by droplets and direct contact, is a global public health issue that causes an average of 2.5 excess infl uenza-like illness (ILI) consultations per 1,000 person-years in China. 1Nonpharmaceutical interventions (NPIs) against droplet and direct contact transmission, including social distancing measures and personal protective measures, are recommended to reduce the spread of disease.Social distancing measures comprised isolating ill persons, quarantining exposed persons, school and workplace closures, and avoiding crowds.Personal protective measures included hygiene, respiratory etiquette, and face masks. 2In December 2019, coronavirus disease 2019 (COVID-19) started to spread, and China introduced NPIs to address the pandemic in January 2020.These NPIs could also help reduce the spread of other respiratory diseases, such as seasonal influenza. 3In the second half of 2020, the COVID-19 pandemic was gradually brought under control.Production, transport, and schools were returning to normal, while citizens were still required to wear masks in public.Cases of influenza also reappeared.This study compared the ILI percentage (ILI%), laboratory (LAB)-positive rate, incidence rate, and effective reproductive number (Rt) of infl uenzas from 2019 to 2022 to clarify the change in seasonal infl uenza spread after the COVID-19 outbreak.