Tetravalent Rhesus-human Rotavirus Vaccine (RRV-TV) in Belem, Brazil: Efficacy against Prevailing P and G Genotypes

To determine the efficacy of a reassortant rhesus-human tetravalent rotavirus vaccine (RRV-TV) (4 x 10(4) pfu/dose) against P and G rotavirus genotypes, 90 positive samples were tested using reverse transcription-polymerase chain reaction. The efficacy of the RRV-TV vaccine against P[8] and G1 individually or in binary combination P[8], G1 was 72 per cent (p < 0.005) 61 per cent (p < 0.013), and 70 per cent (p < 0.009), respectively, only for the first year of follow-up. In the second year, as well as after 2 years of follow-up, no efficacy was observed to these genotypes. These data indicate that further studies with rotavirus vaccines should focus on the molecular characterization of rotaviruses genotypes, in order to see whether or not cross-protection among different G and P genotypes may occur as a result of common bearing of VP4 specificities.