Epidemiological and Clinical Insights into Enterovirus Circulation in Europe, 2018-2023: A Multicenter Retrospective Surveillance Study

Abstract

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

Methods: Aggregated data were requested from the European Centre for Disease Prevention and Control National Focal Points for Surveillance and European Non-Polio Enterovirus Network. Data included detection month, specimen type, age group, and clinical presentation for the 10 most commonly reported EV types per year.

Results: Twenty-eight institutions (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 30 (E30), coxsackievirus A6 (CVA6), EV-D68, E9, E11, CVB5, E18, CVB4, EV-A71, and E6 most frequently reported. E30 declined after 2018/2019, while CVA6, CVB5, E9, E11, and EV-D68 were prevalent both before and after the coronavirus disease 2019 (COVID-19) pandemic, and CVB4 and E18 were prevalent after the pandemic. 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 frequently reported among neonates (18%-32%). CVA6 was frequently associated with hand, foot and mouth disease, and EV-D68 with respiratory infections. Paralysis was reported among 22 infections, associated with 10 nonpolio types.

Conclusions: This study emphasizes the widespread circulation and severity of EV infections in Europe, as well as the (re)emergence of specific types postpandemic. Our findings highlight the need for continuous EV surveillance to monitor variation in circulation, age, and clinical presentations, including paralysis among nonpolio EV infections.

Keywords: Europe; enterovirus; epidemiology; laboratory detection; surveillance.

Figure 1.

Enterovirus (EV)-positive samples per participating country. Total number of EV-positive and -negative tests reported, along with the positivity rate (black triangle), between 2018 and 2023 (n = 563 654). No testing data were reported by Scotland, and no data on the total number of tests were reported from Denmark.

Figure 2.

Enterovirus (EV) type distribution. The overall number of cases associated with each detected EV type between 2018 and 2023 (n = 11 605). The 10 most commonly reported EV types among all participants are indicated in bold. Abbreviations: CV, coxsackievirus; E, echovirus; EV, enterovirus.

Figure 3.

A, Temporal distribution of EV-positive cases, 2018–2023 (n = 10 925). The summer months (June-August) are highlighted in red. B, Relative monthly distribution of 10 most commonly reported EV types. The color intensity in the heat maps is based on the natural logarithm of the fraction of the number of cases of each type over the total number of cases within each month adding up to 100%. Black regions represent either zero infections or no data. Abbreviations: CV, coxsackievirus; E, echovirus; EV, enterovirus.

Figure 4.

Distribution of specimen types among enterovirus-positive samples per year, 2018–2023 (n = 10 925).

Figure 5.

EV detection patterns of the 10 most commonly reported EV types by (A) specimen type (n = 4355), (B) age group (n = 8082), and (C) clinical presentation (n = 2379), normalized per type, between 2018 and 2023. Abbreviations: CSF, cerebrospinal fluid; CV, coxsackievirus; E, echovirus; EV, enterovirus; HFMD, hand, foot, and mouth disease.