Common precautions to prevent the spread of COVID-19, such as social distancing and wearing masks, also decreased the rates of common respiratory illnesses in 2020 and early 2021, according to results published in Open Forum Infectious Diseases in March.
Study results by investigators at Boston Medical Center (BMC) in Massachusetts showed an approximately 80% reduction in cases of influenza and other common viral respiratory infections compared with similar time periods in previous years when school closings, social distancing, and wearing of masks were not widely implemented.
Public health measures used to prevent COVID-19 transmission also can be useful in preventing other respiratory viral infections, according to the study authors.
“We know viruses that cause the common cold and pneumonia are spread through close contact, aerosols, and/or droplets, which is why we decided to look into how the measures implemented to prevent the spread of COVID-19 may have impacted the incidence of other common viral respiratory illnesses,” coinvestigator Manish Sagar, MD, an infectious diseases physician and associate professor of medicine at BMC, said in a statement.
The investigators performed a retrospective cohort analysis to analyze all documented respiratory viral infections at BMC between January 1, 2015, and November 25, 2020. These infections were diagnosed using a comprehensive respiratory panel polymerase chain-reaction test, which the study authors said scans for 20 common respiratory pathogens. Negative and positive results for SARS-CoV-2 tests were excluded, given the focus on other common respiratory illnesses prior to the COVID-19 pandemic.
According to the study, 2020 was divided into 2 periods: before the implementation of closing schools, social distancing, and wearing masks (period 1) and after the implementation of these practices (period 2).
The investigators analyzed the number of viral infections during periods 1 and 2 for 2015 through 2019 and compared them with the 2020 results.
In period 2 of 2020, after the implementation of measures to stop COVID-19, newly detected respiratory viruses were approximately 80% lower compared with 2015 through 2019. But in period 1 of 2020, there were more respiratory virus infections compared with 2015 through 2019.
Furthermore, the investigators noted that the phased reopening in Boston, which began around July 20, 2020, was associated with an increase in the detection of rhinovirus infections.
The findings could help experts develop prevention strategies for future cold and flu seasons even after the COVID-19 pandemic, according to the study authors.
“Our study results may be particularly helpful for developing prevention strategies in settings where respiratory infections are very harmful, such as congregate settings and for the elderly and immunosuppressed,” Sagar said.
Pranay S, Reifler K, Rossi M, Sagar M. COVID-19 mitigation strategies were associated with decreases in other respiratory virus infections. Open Forum Infect Dis. Published online March 20, 2021. doi:10.1093/ofid/ofab105