Comparative analysis of RSV-related hospitalisations in children and adults over a 7 year-period before, during and after the COVID-19 pandemic.

BACKGROUND: RSV is an important cause for respiratory illness in children and the elderly. We analysed RSV seasons since 2016 in both age groups for differences, similarities and timely associations before, during and after the COVID-19 pandemic. METHODS: We studied epidemiological and clinical features of seven consecutive RSV seasons since 2016 retrospectively in children and adults who were systematically monitored for RSV infections by PCR when hospitalized in Regensburg, Germany. RESULTS: Data from 1903 RSV positive, hospitalised patients were analysed (1446 children, 457 adults). We observed a complete absence of RSV associated hospitalizations in season 2020/2021. While in the season of 2021/2022, RSV associated hospitalizations in children returned to considerable numbers earlier than expected, hospitalizations in the elderly were still mitigated during that season in temporal association with the continuation of NPI measures for COVID-19 in the elderly until summer of 2022. Overall, children were hospitalized more often for RSV, while the elderly showed more severe outcomes. RSV hospitalisations continuously increase in both age groups, following a bi-annual pattern of severe and less severe seasons, which was not altered by the COVID-19 pandemic. CONCLUSION: We demonstrate the relation between RSV waves in children and the elderly. NPI measures may protect the elderly from RSV infections and epidemiological data could be used to predict RSV waves early enough to prepare countermeasures.