Rhomboencephalitis outbreak due to enterovirus A71 in children in Catalonia. Advances in prevention

Between April and June 2016, an outbreak of Enterovirus A71 (EV-A71) with rhomboencephalitis-like neurological complications occurred in the paediatric population of Catalonia. EV infections are common and benign in children, with a broad polymorphous clinical spectrum ranging from mild skin manifestations such as exanthematous disease to nervous system involvement with predominance of meningitis over the severe and infrequent encephalitic forms. The existing EV serotypes are currently grouped in four species: A, B, C and D. EV-A71 has caused outbreaks of hand, foot and mouth disease with severe neurological complications. Measures to avoid infection transmission are primarily preventive (hand washing). Outbreaks of EV-A71 with severe and lethal complications have prompted the search for preventive vaccines. Two of these vaccines have been licensed in China in 2016: they are whole inactivated viruses, are adsorbed in aluminium hydroxide and provide protection against all the clinical forms of hand, foot and mouth disease; one of them also protects against herpangina, produced by EV-A71 subgenotype C4, which has been predominant in China since 2008. These vaccines do not provide cross-protection against other EV species. Such peculiarities limit their use in controlling outbreaks in specific geographical areas and only for one subgenotype.