Immunogenicidad, inocuidad y eficacia de una vacuna tetravalente obtenida por recombinaci?n gen?tica de rotavirus aislados de monos rhesus y seres humanos en Bel?m, Brasil

• Autor(a) principal: Linhares, Alexandre da Costa
• Data de Publicação: 1998
• Outros Autores: Gabbay, Yvone Benchimol, Mascarenhas, Joana D'Arc Pereira, Freitas, Ronaldo Barros de, Oliveira, Consuelo Silva de, Bellesi, Newton, Monteiro, Talita Ant?nia Furtado, Lins-Lainson, Z?a Constante, Ramos, Francisco L?zio de Paula, Valente, Sebasti?o Aldo da Silva
• Tipo de documento: Artigo
• Idioma: esp
• Título da fonte: Repositório Digital do Instituto Evandro Chagas (Patuá)
• Texto Completo: http://patua.iec.gov.br//handle/iec/3224
• topic: Rotavirus / patogenicidade; Rotavirus / imunologia; Vacinas contra Rotavirus / administra??o & dosagem; Vacinas contra Rotavirus / imunologia; Vacinas / imunologia; Vacina contra Difteria, T?tano e Coqueluche / imunologia

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 35 in 23% 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.