Enterovirus 71 (EV71) is one of the major causative agents of outbreaks of hand, foot, and mouth disease or herpangina worldwide.
This phase 3 trial was designed to evaluate the efficacy, safety, and immunogenicity of an EV71 vaccine.
Dr Fengcai Zhu and colleagues from China conducted a randomized, double-blind, placebo-controlled, multicenter trial in which 10,007 healthy infants and young children were randomly assigned in a 1:1 ratio to receive 2 intramuscular doses of either EV71 vaccine or placebo, 28 days apart.
The surveillance period was 12 months.
The team's primary end point was the occurrence of EV71-associated hand, foot, and mouth disease or herpangina.
|Vaccine efficacies against EV71-associated hospitalization was 100%|
|New England Journal of Medicine|
During the 12-month surveillance period, EV71-associated disease was identified in 0.3% of vaccine recipients, and 2.1% of placebo recipients in the intention-to-treat cohort.
The team found that this vaccine efficacy against EV71-associated hand, foot, and mouth disease or herpangina was 95% in this cohort.
Vaccine efficacies against EV71-associated hospitalization and hand, foot, and mouth disease with neurologic complications were both 100%.
The team observed that serious adverse events occurred in about 2% of children in the vaccine group, and about 3% of children in the placebo group.
In the immunogenicity subgroup, an anti-EV71 immune response was elicited by the 2-dose vaccine series in 99% of participants at day 56.
The researchers observed that an anti-EV71 neutralizing antibody titer of 1:16 was associated with protection against EV71-associated hand, foot, and mouth disease or herpangina.
Dr Zhu and team comment, "The EV71 vaccine provided protection against EV71-associated hand, foot, and mouth disease or herpangina in infants and young children. "