Real-world effectiveness of EV-A71 vaccine against encephalitis in children

While the EV-A71 vaccine is available, its real-world effectiveness against severe neurological complications such as encephalitis and its influence on circulating enterovirus serotypes require further clarification. This single-center, retrospective study analyzed 7823 children hospitalized with enterovirus-associated hand, foot, and mouth disease or herpangina between 2016 and 2023. Among them, 414 children had received EV-A71 vaccination (376 fully, 38 partially) and 7409 were unvaccinated. Encephalitis, defined by clinical symptoms, neuroimaging evidence, and CSF pleocytosis (>5 WBC/mm3), occurred in 8.5% of vaccinated children compared to 16.7% in unvaccinated children, representing a 49% relative risk reduction (χ2 = 19.768, p p