Impact of COVID-19 pandemic restrictions and subsequent relaxation on the prevalence of respiratory virus hospitalizations in children

Background The COVID-19 pandemic and the consequently adopted worldwide control measures have resulted in global changes in the epidemiology and severity of other respiratory viruses. We compared the number and severity of viral acute lower respiratory tract infection (ALRTI) hospitalizations and determined changes in causative respiratory pathogens before, during, and after the pandemic among young children in Qatar. Methods In this single-center retrospective study, we reviewed data of children <= 36 months old who were admitted to Sidra Medicine in Qatar with a viral ALRTI during winter seasons (September-April) between 2019 and 2023. The study period was divided into three distinct seasons based on the pandemic-imposed restrictions as follows: (1) the period between September 2019 and April 2020 was considered the pre-COVID-19 pandemic season; (2) the periods between September 2020 and April 2021, and the period between January and April 2022 were considered the COVID-19 pandemic seasons; and (3) the periods between September 2022 and April 2023 was considered the post-COVID-19 pandemic season. Results During the COVID-19 season, 77 patients were admitted, compared with 153 patients during the pre-COVID-19 season and 230 patients during the post-COVID-19 season. RSV was the dominant virus during the pre-COVID-19 season, with a detection rate of 50.9%. RSV infection rate dropped significantly during the COVID-19 season to 10.4% and then increased again during the post-COVID-19 season to 29.1% (P < 0.001). Rhinovirus was the dominant virus during the COVID-19 (39.1%) and post-COVID-19 seasons (61%) compared to the pre-COVID-19 season (31.4%) (P < 0.001). The average length of hospital stay was significantly longer in the post-COVID-19 season than in the pre-COVID-19 and COVID-19 seasons (P < 0.001). No significant differences in the pediatric intensive care unit (PICU) admission rate (P = 0.22), PICU length of stay (p = 0.479), or respiratory support requirements were detected between the three seasons. Conclusion Our study showed reduced viral ALRTI hospitalizations in Qatar during the COVID-19 pandemic with reduced RSV detection. An increase in viral ALRTI hospitalizations accompanied by a resurgence of RSV circulation following the relaxation of COVID-19 restrictions was observed without changes in disease severity.