Respiratory syncytial virus (RSV) infection among infants in the first year of life (Czech Republic, 2017-2022).

Objectives: Due to the lack of data on the frequency and seriousness of respiratory syncytial virus (RSV) infection in the Czech Republic among children under 1 year, an analysis was made of available data on hospitalizations and the risk of hospitalization was estimated for different age groups.

Methods: Data from the Registry of Reimbursed Health Services and the National Registry of Hospitalizations were used for the analyses. Hospitalizations and deaths due to RSV infection (diagnoses J12.1, J20.5, J21.0) from 2017-2022 were analysed by month of the first year of life.

Results: Over the study period, there were 4,356 hospitalizations with the above diagnoses, ranging between years from 172 to 1,445. The estimated overall hospitalization risk per 100,000 population and year for diagnoses J12.1, J20.5, and J21.0 was 656.26, varying between 156.29 (2020) and 1,294.12 (2021). Age-group analysis showed the highest risk for children under 6 months of age (953.97/100,000 population per year). They accounted for 72.7% of the total of hospitalizations in patients under 1 year of age, with the highest number of hospitalizations observed in 1-3-month-olds. The most frequent cause of hospitalizations with RSV infection was bronchitis, representing 55.4% of the above diagnoses. During the 6-year period, 3,771 full-term infants and 585 (13.4%) preterm infants were hospitalized. Among those 4,356 hospitalized with diagnoses J12.1, J20.5, and J21.0, 22 deaths (0.5%) were reported.

Conclusions: RSV-associated hospitalizations have been recorded in all age groups in the Czech Republic. The highest RSV-associated hospitalization risk in 2017-2022 was estimated among children under 6 months of age. Passive surveillance using the available registries can be currently considered as an appropriate basis for adopting targeted measures specifically tailored to the youngest age categories.