Enterovirus 71 (EV71) and coxsackieviruses (CV) are the major causative agents of hand, foot and mouth diseases (HFMD) outbreaks worldwide and have a significant socioeconomic impact in particular in Asia. Formalin-inactivated EV71 (FI-EV71) vaccines evaluated in human clinical trials in China, Taiwan and Singapore were found to be safe and to elicit strong neutralizing antibody responses against EV71 currently circulating in Asia. The results from 3 different phase III clinical trials performed in young children (6 to 60 months) indicate that the efficacy of FI-EV71 vaccines is >90% against EV71-related HFMD and >80% against EV71-associated serious diseases, but the vaccines did not protect against CVA16 infections. Here we discuss the critical factors affecting EV71 vaccine product registration, including clinical epidemiology, antigenic shift issues in cross-protection and vaccine strain selection, standardized animal models for potency test, and cost-effective manufacturing processes for potential incorporation of FI-EV71 vaccine into EPI vaccines.
