Impact of the COVID-19 pandemic on other respiratory virus outbreaks

The preventive measures to control the coronavirus disease (COVID-19) pandemic could affect other virus outbreaks. However, any changes in their incidence have not been evaluated. This study aimed to determine how the COVID-19 management policy has influenced the positive rates of other respiratory viruses. We collected data from the weekly reports of Korea Influenza and Respiratory Viruses Surveillance System on eight targeted viruses—adenovirus, human bocavirus, human coronavirus, human metapneumovirus, human rhinovirus, influenza virus, parainfluenza virus, and respiratory syncytial virus—from weeks 1 to 18 per year for the past 10 years. We compared the mean of each week in 2020 with the past 10 years using paired t-test. The study period was divided based on the date of the first COVID-19 case in South Korea (before: weeks 1–4; after: weeks 5–18). The overall positive rate of the respiratory viral infection was 38.7% in 2020 and 62.0% in 2010–2019. The positive rates of respiratory viruses with seasonality—hRV, IFV, and PIV—decreased during the COVID-19 pandemic. Although the positive rate of RSV increased significantly in the early weeks, the changes after week 5 were not significant. This phenomenon may be attributed to the strict COVID-19 control measures.