Randomised placebo-controlled trial of rhesus-human reassortant rotavirus vaccine for prevention of severe rotavirus gastroenteritis

Background Rotavirus is the most common cause of acute childhood gastroenteritis. Vaccination with live oral heterologous rotavirus vaccines may prevent rotavirus gastroenteritis. We assessed the efficacy of rhesus-human reassortant rotavirus tetravalent vaccine (RRV-TV) against severe rotavirus gastroenteritis in Finnish children in a randomised placebo-controlled double-blind trial. Methods Placebo or RRV-TV (titre 4·105 plaque-forming units) was given to infants at ages 2, 3, and 5 months. The children were followed up for one or two rotavirus epidemic seasons. The main outcome measure was protection against severe rotavirus gastroenteritis (score≥11 on a 20-point severity scale). 2398 children were enrolled and received at least one dose of RRV-TV (n=1191) or placebo (n=1207). The primary efficacy analysis was based on children who received three doses of RRV-TV (n=1128) or placebo (n=1145). Findings 256 episodes of rotavirus gastroenteritis occurred at any time during the study; 65 were among 1191 RRV-TV recipients, and 191 among 1207 placebo recipients (vaccine efficacy 66% [95% Cl 55–74]; intention-to-treat analysis). 226 episodes were included in the primary efficacy analysis of fully vaccinated children (54 among 1128 RRV-TV recipients, 172 among 1145 placebo recipients; vaccine efficacy 68% [57–76]). 100 episodes were severe, eight in RRV-TV recipients and 92 in placebo recipients (vaccine efficacy 91% [82–96]). Interpretation RRV-TV vaccine was highly effective against severe rotavirus gastroenteritis in young children. Incorporation of this vaccine into routine immunisation schedules of infants could reduce severe rotavirus gastroenteritis by 90% and severe gastroenteritis of all causes in young children by 60%.