[Impact of COVID-19 pandemic on the etiology and severity of respiratory viral infections in children].

OBJECTIVE

To analyze the age-related characteristics of the contribution of influenza viruses, RSV, SARS-CoV-2, other pathogens to the development of severe acute respiratory infections (SARI) in children with an assessment of the disease severity depending on its etiology and epidemic period.

MATERIALS AND

METHODS

SARI monitoring was carried out over six consecutive epidemic seasons, starting from 2018-2019 in 9 infectious hospitals of three cities of Russia with an assessment of the disease severity depending on its etiology.

RESULTS

Among all hospitalized children, the proportion of children hospitalized with laboratory-confirmed influenza from 2018 to 2020 ranged from 25.7% to 44.7%, and for RSV infection from 25.7% to 26.8%. However, during the peak of the pandemic, these rates dropped significantly to 0.3% and 1.7%, respectively. In the subsequent three seasons (2021-2024), laboratory-confirmed influenza among hospitalized children was registered in 4.5-20.2% of cases, while RSV infection was identified in 13.4-24.1% of cases, accompanied by a shift in viral subgroups. RSV infections were most severe during the 2022-2023 season, presenting in some cases with hyperthermia, hypoxia, dyspnea, and altered consciousness. Among hospitalized children, the proportion with COVID-19 was relatively low in 2020-2021 (0.8-2.4%) but increased significantly to 10.6%-13.6% following the emergence of the Omicron variant in 2022, before decreasing again in subsequent years. The main genetic lineages of SARS-CoV-2 circulating in the Russian Federation are presented.

CONCLUSION

Influenza and RSV viruses were predominant among viral pathogens identified in hospitalized children aged ≤ 2 years. COVID-19 cases among children were relatively rare and generally less severe compared to RSV and rhinovirus infections.