New research shows that in 2020-2021, while the circulation of influenza, RSV, and other respiratory viruses declined sharply, rhinovirus/enterovirus – which causes the common cold – persisted and continued to circulate among children, according to a study presented at IDWeek 2021.

Using CDC’s New Vaccine Surveillance Network (NVSN), researchers enrolled 37,676 children across seven US medical centers between December 2016 through January 2021. From March 2020 to January 2021, the overall percentage of enrolled children who had detectable rhinovirus was similar to the same time period in 2017-2018 and 2019-2020. In contrast, the proportion of influenza, RSV, and other respiratory viruses combined declined significantly when compared to all three prior seasons.

“It has been previously shown that mitigation measures, like mask wearing or social distancing, which were introduced to limit the spread of SARS-CoV-2, also limited the spread of influenza, RSV, and some other respiratory viruses,” says Danielle Rankin, MPH, CIC, presenting author of the study and doctoral candidate at Vanderbilt University. “This study showed rhinovirus/enterovirus slightly decreased in March 2020, but shortly after resumed and persisted.”

The study is part of a multi-center, active prospective acute respiratory illness study in children that began in 2016. NVSN enabled the researchers to evaluate the circulation of rhinovirus over time. 

“The fact that we continued to see rhinovirus says there is something virologically different about it,” says Natasha Halasa, MD, MPH, co-author of the study and the Craig Weaver Professor of Pediatrics at Vanderbilt University Medical Center. “The next question is, which specific rhinovirus types, and why?”

Study authors will continue to investigate the circulation of respiratory viruses to better understand the virologic, behavioral, and environmental factors that contribute to the persistent circulation of rhinovirus.