In Mexico, a rise by one factor of 2 in the chance of intussusception after vaccination was noted during the second and third weeks after dose 2 however, not during the initial week after dose 2. This pattern of risk is not in keeping with the pattern of vaccine-virus replication, which peaks during the 1st week after vaccination,20 raising queries about the biologic plausibility of the association. In Brazil, however, a little but significant increase in risk was mentioned in the initial week after dose 2, which would be consistent with the timing of replication of the vaccine virus. It is possible that because of the reduced immunogenicity of the first dosage of RV1 when it is provided with the oral poliovirus vaccine, since it can be in Brazil, the second dosage of RV1 would efficiently be the 1st immunizing dose in some infants and could be associated with better replication of the vaccine virus.Laboratory-Confirmed Influenza A total of 119 participants had laboratory-confirmed symptomatic influenza : 108 had influenza A and 11 had influenza B. In 90 individuals , including all 11 with influenza B, the virus was identified by isolation in cell culture, and all 90 isolates were verified by real-period PCR assays; in 29 situations the virus was determined by real-period PCR assay just. Estimates of Complete and Relative Vaccine Efficacy With the use of culture alone to verify cases of influenza, the absolute efficacy was 73 percent for the inactivated vaccine and 51 percent for the live attenuated vaccine. When it comes to relative efficacy, there is a 45 percent reduction in culture-confirmed cases of influenza among recipients of the inactivated vaccine as compared with recipients of the live attenuated vaccine .