Immunogenicity and Safety of Inactivated Enterovirus 71 Vaccine in Children Aged 36-71 Months: A Double-Blind, Randomized, Controlled, Non-inferiority Phase III Trial

Abstract

Background: The Sinovac enterovirus 71 (EV71) vaccine has been given to children aged 6-35 months with good safety, immunogenicity, and efficacy. Further exploration is needed for the application of Sinovac EV71 vaccine in older children.

Methods: A phase III, double-blind, single-center, randomized, controlled, non-inferiority, and bridging-designed trial enrolled 300 participants aged 6-35 months and 600 participants aged 36-71 months. Non-inferiority and superiority analyses were made to determine the immunogenicity of Sinovac EV71 vaccine in older children (Older-S group), comparing with that of control EV71 vaccine in the same age group (Older-C group), or comparing with that of Sinovac EV71 vaccine in younger children (Younger-S group).

Results: The seroconversion rate of anti-EV71 in Older-S group (95.5%) was superior to that of Older-C group (86.0%), and non-inferior to that of Younger-S group (98.5%). For baseline seronegative participants, the geometric mean titer of Older-S group (370.0) was non-inferior to that of Older-C group (296.2) and superior to that of Younger-S group (176.5). Incidence of adverse reactions in Older-S group (47.0%) was similar to that of Older-C group (44.8%), or Younger-S group (49.8%).

Conclusions: This study showed good safety and immunogenicity of Sinovac EV71 vaccine in children aged 36-71 months.

Clinical trials registration: NCT03909074.

Url: https://clinicaltrials.gov/ct2/show/NCT03909074?term=NCT03909074&draw=2&rank=1.

Keywords: Sinovac enterovirus 71 vaccine; children aged 36–71 months; hand, foot, and mouth disease; immunogenicity; safety.