Seasonal and inter-seasonal RSV activity in the European Region during the COVID-19 pandemic from Autumn 2020 to Summer 2022

Abstract

Background: The emergence of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in early 2020 and subsequent implementation of public health and social measures (PHSM) disrupted the epidemiology of respiratory viruses. This work describes the epidemiology of RSV observed during two winter seasons (weeks 40 to 20) and inter-seasonal periods (weeks 21 to 39) during the pandemic between October 2020 and September 2022. Methods: Using data submitted to The European Surveillance System (TESSy) by countries or territories in the World health Organization (WHO) European Region between weeks 40/2020 and 39/2022, we aggregated country-specific weekly RSV counts of sentinel, non-sentinel and Severe Acute Respiratory Infection (SARI) surveillance specimens and calculated percentage positivity. Results for both 2020/21 and 2021/22 seasons and inter-seasons were compared to pre-pandemic 2016/17 to 2019/20 seasons and inter-seasons. Results: Although more specimens were tested than in pre-COVID-19 pandemic seasons, very few RSV detections were reported during the 2020/21 season in all surveillance systems. During the 2021 inter-season, a gradual increase in detections was observed in all systems. In 2021/22, all systems saw early peaks of RSV infection, and during the 2022 inter-seasonal period, patterns of detections were closer to those seen before the COVID-19 pandemic. Conclusion: RSV surveillance continued throughout the COVID-19 pandemic, with an initial reduction in transmission, followed by very high and out-of-season RSV circulation (summer 2021) and then an early start of the 2021/22 season. RSV circulation during the 2022/23 season had not yet normalised.

Clinical Differences between SARS-CoV-2 and RSV Infections in Infants: Findings from a Case–Control Study

“…A European (including data from our country) surveillance study of epidemiology aspects during the SARS-CoV-2 pandemic [12] documented a decrease in RSV circulation to a low rate of positivity, 1% of specimens, from more than 21,000 primary care sentinel surveillance centers. Only France and Switzerland documented clear waves of RSV activity, and France, Germany, and Slovenia recorded an early start to their seasonal 2021-2022 cir-culation compared with the average starting week in pre-COVID-19 pandemic seasons [12]. This important change in circulation paradigm was also documented in other parts of the world, where RSV circulates during the winter months, such as in Australia and New Zealand [13] and South Africa [14].…”