Herpangina

This multicenter, randomized, double-blind, placebo-controlled phase IIIa clinical trial aims to evaluate the protective efficacy , immunogenicity and safety of the Tetravalent Inactivated Enterovirus Vaccine (Vero Cell) in Children aged 6 to 71 months. Participants will be randomly assigned in a 1:1 ratio to the trial group and the placebo group, receiving two doses of experimental vaccine or placebo , with a one-month interval between the two doses.

The aims of this prospective multicentric study is to determine the types of enteroviruses (EVs) responsible for hand, foot and mouth disease (HFMD) or herpangina in children seen within an ambulatory setting : * to detect an EV-A71 epidemic or another type associated with atypical forms of the disease at an early stage * to describe and compare the epidemiological, demographic, clinical and virological characteristics of these infections between the different types of EV.