Febrile young infants and the association with enterovirus infection

Background: Enterovirus is a common pediatric infectious disease, but the epidemiological data in young infants were lacking. This study aims to evaluate the role of enterovirus in febrile young infants and identify risk factors for severe infections. Methods: We enrolled febrile infants younger than 90 days admitted to National Taiwan University Hospital from January 2010 to June 2021. Enterovirus infection was confirmed via viral isolation or pan-enterovirus PCR. Central nervous system involvement was defined by positive culture or PCR in cerebrospinal fluid. Severe complications included sepsis, hepatic failure, myocarditis, shock, encephalitis, acute kidney injury, respiratory failure, and multiorgan failure. Results: Out of 840 febrile infants, 17.4% (n = 146) had enterovirus infection. Among these, 46% (n = 67) presented with meningitis and/or encephalitis. Early-onset enterovirus infection within the first two weeks of life was significantly linked to increased risks of anemia (hemoglobin <9 g/dL), ICU admission, central nervous system involvement, shock, hepatic failure, and mortality. Multivariable logistic regression identified high-risk serotypes (aOR 17.4, [95% CI 1.58, 191.5], p = 0.019) and hemoglobin <9 g/dL (aOR 44.9, [95% CI 5.6, 357.6], p < 0.001) as significant risk factors for severe complications. Conclusion: Enterovirus accounted for 17.4% of the etiology in febrile young infants and the case-fatality rate was 2%. Febrile young infants who had risk factors of enterovirus infection should consider viral culture or PCR examination for confirmation.