Affiliation:
1. Unit 36, Respiratory Infections, Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
2. Unit 17, Influenza and Other Respiratory Viruses, Department of Infectious Diseases, Consultant Laboratory for RSV, PIV and HMPV, Robert Koch Institute, Berlin, Germany
3. Unit 17, Influenza and Other Respiratory Viruses, Department of Infectious Diseases, National Influenza Centre, Robert Koch Institute, Berlin, Germany
4. HELIOS KLINIKEN GmbH, Berlin, Germany
Abstract
Background
Non-pharmaceutical interventions (NPIs) during the COVID-19 pandemic affected respiratory syncytial virus (RSV) circulation worldwide.
Aim
To describe, for children aged < 5 years, the 2021 and 2022/23 RSV seasons in Germany.
Methods
Through data and 16,754 specimens from outpatient sentinel surveillance, we investigated RSV seasonality, circulating lineages, and affected children’s age distributions in 2021 and 2022/23. Available information about disease severity from hospital surveillance was analysed for patients with RSV-specific diagnosis codes (n = 13,104). Differences between RSV seasons were assessed by chi-squared test and age distributions trends by Mann–Kendall test.
Results
RSV seasonality was irregular in 2021 (weeks 35–50) and 2022/23 (weeks 41–3) compared to pre-COVID-19 2011/12–2019/20 seasons (median weeks 51–12). RSV positivity rates (RSV-PR) were higher in 2021 (40% (522/1,291); p < 0.001) and 2022/23 (30% (299/990); p = 0.005) than in prior seasons (26% (1,430/5,511)). Known globally circulating RSV-A (lineages GA2.3.5 and GA2.3.6b) and RSV-B (lineage GB5.0.5a) strains, respectively, dominated in 2021 and 2022/23. In 2021, RSV-PRs were similar in 1 – < 2, 2 – < 3, 3 – < 4, and 4 – < 5-year-olds. RSV hospitalisation incidence in 2021 (1,114/100,000, p < 0.001) and in 2022/23 (1,034/100,000, p < 0.001) was approximately double that of previous seasons’ average (2014/15–2019/20: 584/100,000). In 2022/23, proportions of RSV patients admitted to intensive care units rose (8.5% (206/2,413)) relative to pre-COVID-19 seasons (6.8% (551/8,114); p = 0.004), as did those needing ventilator support (6.1% (146/2,413) vs 3.8% (310/8,114); p < 0.001).
Conclusions
High RSV-infection risk in 2–4-year-olds in 2021 and increased disease severity in 2022/23 possibly result from lower baseline population immunity, after NPIs diminished exposure to RSV.
Publisher
European Centre for Disease Control and Prevention (ECDC)
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