The changing pattern of common respiratory and enteric viruses among outpatient children in Shanghai, China: Two years of the COVID-19 pandemic

Abstract

Nonpharmaceutical interventions (NPIs) taken to combat the coronavirus disease 2019 (COVID-19) pandemic have not only decreased the spread of severe acute respiratory syndrome coronavirus 2 but also have had an impact on the prevalence of other common viruses. This study aimed to investigate the long-term impact of NPIs on common respiratory and enteric viruses among children in Shanghai, China, as NPIs were relaxed after June 2020. The laboratory results and clinical data of outpatient children with acute respiratory tract infections (ARTI) and acute gastroenteritis (AGE) were analyzed and compared between the post-COVID-19 period (from June 2020 to January 2022) and pre-COVID-19 period (from June 2018 to January 2020). A total of 107 453 patients were enrolled from June 2018 to January 2022, including 43 190 patients with ARTI and 64 263 patients with AGE. The positive rates of most viruses decreased during the post-COVID-19 period, with the greatest decrease for influenza A (-0.94%), followed by adenoviruses (AdV) (-61.54%), rotaviruses (-48.17%), and influenza B (-40%). However, the positive rates of respiratory syncytial virus (RSV) and enteric AdV increased during the post-COVID-19 period as the NPIs were relaxed. Besides this, in the summer of 2021, an unexpected out-of-season resurgence of RSV activity was observed, and the resurgence was more prominent among children older than 5 years. The effectiveness of the current relaxed NPIs in control of common respiratory and enteric viruses was variable. Relaxation of NPIs might lead to the resurgence of common viruses.

Keywords: COVID-19; children; enteric viruses; nonpharmaceutical interventions; outpatient; respiratory viruses.

Figure 1

Seasonal activity of respiratory and enteric viruses over the study period. (A) RV and RSV; (B) FluA and FluB; and (C) enteric AdV and AdV (respiratory infection). Gray block represents the period of the “COVID‐19 pandemic” when strict nationwide NPIs were implemented and schools were closed. AdV, adenoviruses; COVID‐19, coronavirus disease 2019; FluA, influenza virus A; FluB, influenza virus B; NPI, nonpharmaceutical intervention; RSV, respiratory syncytial virus; RV, rotaviruses.

Figure 2

Percent change in the positive rate during the post‐COVID‐19 period compared with the pre‐COVID‐19 period and stratified by age and sex. (A) Percent change by age and (B) percent change by sex. AdV, adenoviruses; COVID‐19, coronavirus disease 2019; FluA, influenza virus A; FluB, influenza virus B; RSV, respiratory syncytial virus; RV, rotaviruses.