Epidemiological and clinical insights into enterovirus circulation in Europe, 2018 - 2023: a multi-center retrospective surveillance study.

Abstract

Background: Enteroviruses (EV) cause yearly outbreaks with severe infections, particularly in young children. This study investigates EV circulation, age-distribution, and clinical presentations in Europe from 2018-2023.

Methods: Aggregated data were requested from ECDC National Focal Points for Surveillance and European Non-Polio Enterovirus Network. Data included detection month, specimen type, age-group, and clinical presentation for the ten most commonly reported EV types per year.

Findings: Twenty-eight institutions from 16 countries reported 563,654 EV-tests during the study-period with 33,265 (5.9%) EV-positive. Forty-two types were identified (n=11,605 cases) with echovirus (E)30, coxsackievirus (CV)A6, EV-D68, E9, E11, CVB5, E18, CVB4, EV-A71, and E6 most frequently reported. E30 detection declined after 2018/2019, while CVA6, CVB5, E9, E11, and EV-D68 were prevalent both before and after the COVID-19 pandemic, and CVB4 and E18 were prevalent after the pandemic. Over the study period, a shift in seasons (summer to fall) and specimen positivity (feces to respiratory) was observed. Neurological signs predominated among EV-A71, CVB4, CVB5, E6, E9, E11, E18, and E30 (30-72%). CVB4, CVB5, E9, E11, and E18 were also frequently reported among neonates (18-32%). CVA6 was frequently associated with HFMD, and EV-D68 with respiratory infections. Paralysis was reported among 22 infections, associated with ten non-polio types.

Conclusion: This study emphasizes the widespread circulation and severe nature of EV infections in Europe, particularly among neonates, as well as the (re-)emergence of specific types post-pandemic. Our findings highlight the need for continuous EV-surveillance to monitor variation in circulation, age, and clinical presentations, including paralysis among non-polio EV infections.