Effect of human rotavirus vaccine on severe diarrhea in African infants.

BACKGROUND: Rotavirus is the most common cause of severe gastroenteritis among young children worldwide. Data are needed to assess the efficacy of the rotavirus vaccine in African children. METHODS: We conducted a randomized, placebo-controlled, multicenter trial in South Africa (3166 infants; 64.1% of the total) and Malawi (1773 infants; 35.9% of the total) to evaluate the efficacy of a live, oral rotavirus vaccine in preventing severe rotavirus gastroenteritis. Healthy infants were randomly assigned in a 1:1:1 ratio to receive two doses of vaccine (in addition to one dose of placebo) or three doses of vaccine--the pooled vaccine group--or three doses of placebo at 6, 10, and 14 weeks of age. Episodes of gastroenteritis caused by wild-type rotavirus during the first year of life were assessed through active follow-up surveillance and were graded with the use of the Vesikari scale. RESULTS: A total of 4939 infants were enrolled and randomly assigned to one of the three groups; 1647 infants received two doses of the vaccine, 1651 infants received three doses of the vaccine, and 1641 received placebo. Of the 4417 infants included in the per-protocol efficacy analysis, severe rotavirus gastroenteritis occurred in 4.9% of the infants in the placebo group and in 1.9% of those in the pooled vaccine group (vaccine efficacy, 61.2%; 95% confidence interval, 44.0 to 73.2). Vaccine efficacy was lower in Malawi than in South Africa (49.4% vs. 76.9%); however, the number of episodes of severe rotavirus gastroenteritis that were prevented was greater in Malawi than in South Africa (6.7 vs. 4.2 cases prevented per 100 infants vaccinated per year). Efficacy against all-cause severe gastroenteritis was 30.2%. At least one serious adverse event was reported in 9.7% of the infants in the pooled vaccine group and in 11.5% of the infants in the placebo group. CONCLUSIONS: Human rotavirus vaccine significantly reduced the incidence of severe rotavirus gastroenteritis among African infants during the first year of life. (ClinicalTrials.gov number, NCT00241644.)

Effect of human rotavirus vaccine on severe diarrhea in African infants.

BACKGROUND: Rotavirus is the most common cause of severe gastroenteritis among young children worldwide. Data are needed to assess the efficacy of the rotavirus vaccine in African children. METHODS: We conducted a randomized, placebo-controlled, multicenter trial in South Africa (3166 infants; 64.1% of the total) and Malawi (1773 infants; 35.9% of the total) to evaluate the efficacy of a live, oral rotavirus vaccine in preventing severe rotavirus gastroenteritis. Healthy infants were randomly assigned in a 1:1:1 ratio to receive two doses of vaccine (in addition to one dose of placebo) or three doses of vaccine - the pooled vaccine group - or three doses of placebo at 6, 10, and 14 weeks of age. Episodes of gastroenteritis caused by wild-type rotavirus during the first year of life were assessed through active follow-up surveillance and were graded with the use of the Vesikari scale. RESULTS: A total of 4939 infants were enrolled and randomly assigned to one of the three groups; 1647 infants received two doses of the vaccine, 1651 infants received three doses of the vaccine, and 1641 received placebo. Of the 4417 infants included in the per-protocol efficacy analysis, severe rotavirus gastroenteritis occurred in 4.9% of the infants in the placebo group and in 1.9% of those in the pooled vaccine group (vaccine efficacy, 61.2%; 95% confidence interval, 44.0 to 73.2). Vaccine efficacy was lower in Malawi than in South Africa (49.4% vs. 76.9%); however, the number of episodes of severe rotavirus gastroenteritis that were prevented was greater in Malawi than in South Africa (6.7 vs. 4.2 cases prevented per 100 infants vaccinated per year). Efficacy against all-cause severe gastroenteritis was 30.2%. At least one serious adverse event was reported in 9.7% of the infants in the pooled vaccine group and in 11.5% of the infants in the placebo group. CONCLUSIONS: Human rotavirus vaccine significantly reduced the incidence of severe rotavirus gastroenteritis among African infants during the first year of life. (ClinicalTrials.gov number, NCT00241644.).

Safety, reactogenicity and immunogenicity of the human rotavirus vaccine in preterm European Infants: a randomized phase IIIb study.

BACKGROUND: Rotavirus disease is more severe in preterm infants than in full-term infants. This study assessed the safety, reactogenicity and immunogenicity of a human rotavirus vaccine, RIX4414, in European preterm infants. METHODS: A total of 1009 preterm infants were randomized (2:1, vaccine:placebo) and stratified into 2 groups: 20% of early (27-30 weeks, group 1) and 80% of late (31-36 weeks, group 2) gestational age preterm infants in each group. Two doses of RIX4414/placebo were administered to these preterm infants according to the recommended chronologic age for full-term infants with an interval of 30-83 days between doses. Serious adverse events were recorded throughout the study period. Solicited and unsolicited adverse events were recorded for 15 and 31 days post-each dose. Antirotavirus IgA concentrations (enzyme-linked immunosorbent assay cutoff = 20 U/mL) and geometric mean concentration were determined pre-dose 1 and 30-83 days post-dose 2 in a subset of 300 infants. This study is registered with ClinicalTrials.gov, number NCT00420745 (eTrack106481). RESULTS: Serious adverse events were reported at a similar frequency in both groups (P = 0.266). Fifty-seven infants reported at least 1 serious adverse event (5.1% [3.5-7.0] in the RIX4414 group and 6.8% [4.3-10.0] in the placebo group). During the 15-day postvaccination follow-up period, diarrhea, vomiting and fever occurred at a similar frequency in both groups; fever could have been due to concomitant vaccines. Five cases (RIX4414 = 3, Placebo = 2) of rotavirus gastroenteritis were reported. The onset of rotavirus gastroenteritis in the RIX4414 group was 1-5 days after vaccination (vaccine strain identified in all cases) and in the placebo group it was 3-4 days after receiving placebo (wild-type rotavirus identified from both cases). Antirotavirus IgA seroconversion rates at 30-83 days post-dose 2 were 85.7% (79.0-90.9) in the RIX4414 group and 16.0% (8.8-25.9) in the placebo group. Geometric mean concentrations were 202.2 U/mL (153.1-267.1) in the RIX4414 group and <20 U/mL in the placebo group. Seroconversion rate in groups 1 and 2 in RIX4414 recipients were 75.9% (95% confidence interval [CI]: 56.5-89.7%) and 88.1% (95% CI: 80.9-93.4%), respectively; the geometric mean concentrations in the respective groups were 110.2 U/mL (95% CI: 56.1-216.5) and 234.8 U/mL (95% CI: 173.4-318.0; exploratory analysis). CONCLUSIONS: Two doses of RIX4414 were immunogenic and well-tolerated in European preterm infants.