Fig. 1

Schematic representation of the phase III clinical trial of an inactivated enterovirus 71 vaccine. In total, 14,445 children, aged 6–71 months, were assessed for a phase III clinical trial and 12,000 eligible volunteers were randomly assigned to receive the vaccine or a placebo [8]. The blood samples of 1,100 individuals were collected at 0, 56, 180, 360, 540, and 720 days after immunization to evaluate the production of anti-EV71 neutralizing antibodies. The follow-up rates (%) are indicated for each time point