title: Immunogenicity, safety and efficacy of tetravalent rhesus-human, reassortant rotavirus vaccine in Belém, Brazil.
abstract: A tetravalent rhesus-human reassortant rotavirus (RRV-TV) vaccine (4 x 10(4) plaque-forming units/dose) was evaluated for safety, immunogenicity and efficacy in a prospective, randomized, double-blind, placebo-controlled trial involving 540 Brazilian infants. Doses of vaccine or placebo were given at ages 1, 3 and 5 months. No significant differences were noted in the occurrence of diarrhoea or vomiting in vaccine and placebo recipients following each dose. Low-grade fever occurred on days 3-5 in 2-3% of vaccinees after the first dose, but not after the second or third doses of vaccine. An IgA antibody response to rhesus rotavirus (RRV) occurred in 58% of vaccinees and 33% of placebo recipients. Neutralizing antibody responses to individual serotypes did not exceed 20% when measured by fluorescent focus reduction, but exceeded 40% when assayed by plaque reduction neutralization. There were 91 cases of rotavirus diarrhoea among the 3-dose (vaccine or placebo) recipients during two years of follow-up, 36 of them among children given the vaccine. Overall vaccine efficacy was 8% (P = 0.005) against any diarrhoea and 35% (P = 0.03) against any rotavirus diarrhoea. Protection during the first year of follow-up, when G serotype 1 rotavirus predominated, was 57% (P = 0.008), but fell to 12% in the second year. Similar results were obtained when analysis was restricted to episodes in which rotavirus was the only identified pathogen. There was a tendency for enhanced protection by vaccine against illness associated with an average of 6 or more stools per day. These results are sufficiently encouraging to warrant further studies of this vaccine in developing countries using a higher dosage in an attempt to improve its immunogenicity and efficacy.
authors.affiliation: Instituto Evandro Chagas, Para, Brazil.
authors.forename: A C
authors.initials: AC
authors.lastname: Linhares
authors.forename: Y B
authors.initials: YB
authors.lastname: Gabbay
authors.forename: J D
authors.initials: JD
authors.lastname: Mascarenhas
authors.forename: R B
authors.initials: RB
authors.lastname: de Freitas
authors.forename: C S
authors.initials: CS
authors.lastname: Oliveira
authors.forename: N
authors.initials: N
authors.lastname: Bellesi
authors.forename: T A
authors.initials: TA
authors.lastname: Monteiro
authors.forename: Z
authors.initials: Z
authors.lastname: Lins-Lainson
authors.forename: F L
authors.initials: FL
authors.lastname: Ramos
authors.forename: S A
authors.initials: SA
authors.lastname: Valente
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000302:isolation & purification; D004311:Double-Blind Method; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007231:Infant, Newborn; D008253:Macaca mulatta; D011446:Prospective Studies; D012401:Rotavirus / Q000145:classification / Q000276:immunology*; D012400:Rotavirus Infections / Q000276:immunology / Q000517:prevention & control*; D012703:Serotyping; D014765:Viral Vaccines / Q000276:immunology / Q000592:standards*
chemical_list: D000914:Antibodies, Viral; D014765:Viral Vaccines