Surveillance of common respiratory infections during the COVID-19 pandemic demonstrates the preventive efficacy of non-pharmaceutical interventions

OBJECTIVE: The emergence of a novel coronavirus, SARS-CoV-2, and its subsequent spread outside of Wuhan, China, led to the human society experiencing a pandemic of coronavirus disease 2019 (COVID-19). While the development of vaccines and pharmaceutical treatments are ongoing, government authorities in China have implemented unprecedented non-pharmaceutical interventions as primary barriers to curb the spread of the deadly SARS-CoV-2 virus. Although the decline of COVID-19 cases coincided with the implementation of such interventions, we searched for evidence to demonstrate the efficacy of these interventions, since artifactual factors, such as the environment, the pathogen itself, and the phases of epidemic, may also alter the patterns of case development. METHODS: We surveyed common viral respiratory infections that have a similar pattern of transmission, tropism, and clinical manifestation, as COVID-19 under a series of non-pharmaceutical interventions during the current pandemic season. We then compared this data with historical data from previous seasons without such interventions. RESULTS: Our survey showed that the rates of common respiratory infections, such as influenza and respiratory syncytial virus infections, decreased dramatically from 13.7% (95% CI, 10.82–16.58) and 4.64% (95% CI, 2.88–7.64) in previous years to 0.73% (95% CI, 0.02–1.44) and 0.0%, respectively, in the current season. CONCLUSIONS: Our surveillance provides compelling evidence that non-pharmaceutical interventions are cost-effective ways to curb the spread of contagious agents, and may represent the only practical approach to limit the evolving epidemic until specific vaccines and pharmaceutical treatments are available.