RESUMEN
BACKGROUND: Live oral rhesus-rhesus-human rotavirus reassortant tetravalent (RRV-TV) vaccine was efficacious against rotavirus gastroenteritis but was withdrawn because of a rare association with intussusception. A corresponding tetravalent (types G1, G2, G3, and G4) reassortant vaccine based on bovine-human (UK) rotavirus reassortant tetravalent (BRV-TV) vaccine was developed concurrently. METHODS: Before the withdrawal of RRV-TV vaccine, parallel placebo-controlled trials of BRV-TV vaccine (observer blinded) versus RRV-TV vaccine (double blinded) with a 2 : 1 ratio of vaccine : placebo were conducted in Finland in a total of 510 infants. Two doses of study vaccine or placebo were administered at ages 3 and 5 months. RESULTS: The first dose of RRV-TV vaccine was followed by a significant excess rate of febrile reactions (36%), whereas the rate of fever after the administration of BRV-TV vaccine did not differ significantly from that in the placebo group. Neither vaccine induced diarrhea. A seroresponse was detected in 97% of BRV-TV vaccine recipients and 94% of RRV-TV vaccine recipients. Both vaccines were equally effective, with 68%-69% efficacy against any and 88%-100% efficacy against severe rotavirus gastroenteritis during the first epidemic season. CONCLUSIONS: BRV-TV vaccine is a promising new candidate rotavirus vaccine, with low reactogenicity and high efficacy. Two doses of BRV-TV or RRV-TV vaccine are sufficient for the induction of protection against severe rotavirus disease.