Enterovirus B types cause severe infection in infants aged 0–3 months

BACKGROUND: Enterovirus (EV) infections are being increasingly seen in younger infants, often being more severe than in older children. The risk factors of EV infection in infants have been inadequately investigated till date. METHODS: We conducted a retrospective study on hospitalized children with laboratory-confirmed EV infection (50 infants aged 0–3 months and 65 older than 3 months) at a tertiary care center in China. Prevalence, clinical characteristics, and genetic features of the virus were analyzed, and independent predictors for severe infection were assessed. RESULTS: Clinical findings showed that severe infection was more common in infants aged 0–3 months than in older children (78.0% vs. 35.4%, p < 0.001), with higher morbidity of pneumonia, meningitis, and sepsis (p < 0.01). EV-B types were detected more frequently in infants aged 0–3 months than in older children (88.0% vs. 7.7%, p < 0.001). Echovirus 11 was the most identified EV-B, and it recombined with E6 in P2 and P3 regions. Risk factors for severe EV infection included EV-B types infection, age less than 3 months, elevated alanine aminotransferase level, abnormal platelet count, and abnormal cerebrospinal fluid characteristics. CONCLUSIONS: Our data indicated that EV-B types mainly cause severe infection in infants aged 0–3 months. Therefore, knowledge about EV-B types could have implications in designing effective intervention and prevention strategies for young infants with severe EV infection. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12985-023-01965-9.