The Importance of Monitoring Viral Respiratory Infections During the COVID-19 Crisis

Abstract

Coronavirus disease 2019 (COVID-19), a new, infec-tious, pneumonia-like disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has continued to spread rapidly worldwide, even in 2021. The COVID-19 outbreak has brought about some changes in influenza and respiratory syncy-tial virus (RSV) and rhinovirus infections, which were previously the main causes of viral pneumo-nia. This review discusses the epidemiology of these infectious diseases during the COVID-19 pandemic. Although influenza cases have been substantially de-creasing worldwide, RSV infection cases, which had temporarily decreased initially, have started to in-crease again, and rhinovirus infection cases have been reported to be higher than usual. The authors re-viewed the viral interferences among these infections in detail because they could exert considerable effect on epidemiological surveillance data. Based on experimental data, a recent study suggested that the influenza virus could promote SARS-CoV-2 infectiv-ity. A previous study reported that influenza A virus inhibits RSV replication in an animal model. An-other recent study revealed that although the replication of rhinovirus is not affected by SARS-CoV-2, the replication of SARS-CoV-2 is inhibited by rhinovirus, indicating that rhinovirus infection protects against SARS-CoV-2. Further studies are required to confirm these findings and evaluate the impact of SARS-CoV-2 on the activity of these viruses.