Rotavirus vaccine RIX4414 efficacy sustained during the third year of life: a randomized clinical trial in an Asian population.

RIX4414 (Rotarix™), has shown high efficacy during the first 2-years of life. A 2-year randomized, double-blind, placebo-controlled trial in Singapore, Hong Kong, and Taiwan was extended for another year. Infants (6-17 weeks) received 2-doses (1-2 months apart) of RIX4414 (n=5359) or placebo (n=5349). During the third-year follow-up, 4359 (RIX4414) and 4328 (placebo) infants were monitored. 64 (1.2%) and 2 (0.04%) infants in the placebo and RIX4414 groups, respectively, reported severe rotavirus-gastroenteritis (RVGE), resulting in a vaccine efficacy of 96.9% (95% CI [88.3-99.6]). Efficacy was 100% (67.5-100) in the third-year. RIX4414 was efficacious against G1 (100.0% [84.8-100]) and pooled non-G1 RV types (94.9% [80.2-99.4]). This study shows that the vaccine is highly efficacious, regardless of circulating RV-types, up to the first 3 years of life in affluent Asian urban populations.