Background: This study tested the hypothesis that the immunogenicity and safety of the simultaneous administration of enterovirus 71 (EV71) vaccine (dose 1) with recombinant hepatitis B vaccine (HepB) on day 1 and EV71 vaccine (dose 2) with group A meningococcal polysaccharide vaccine (MenA) on day 30 is not inferior to separate administration of each vaccine.
Methods: The study was designed as a randomized, open-label, noninferiority trial. A total of 775 healthy infants aged 6 months were randomly assigned in a ratio of 1:1:1 to receive simultaneous administration of EV71 vaccine (dose 1) and HepB on day 1 and EV71 vaccine (dose 2) and MenA on day 30 (the SI group); administration of doses 1 and 2 of EV71 vaccine on days 1 and 30, respectively (the SE1 group); or administration of HepB and MenA on days 1 and 30, respectively (the SE2 group).