1) . This study was conducted in 4 Latin American countries (Mexico, Costa Rica, Guatemala, and Brazil) where OPV was given at ∼2, 4, and 6 months of age. RotaTeq® was given either
click here at the same time as OPV or 2–4 weeks before OPV. After vaccination with the full 3-dose RotaTeq® series, antirotavirus IgA GMC was 47% lower when RotaTeq® was given with OPV (155 U/mL; 95% CI = 126–190) compared to when RotaTeq® was given separately from OPV (293 U/mL; 95% CI = 249–345), with non-overlapping confidence limits. Seroconversion (defined as ≥3-fold rise in serum antirotavirus IgA level) was 5% lower without OPV (93%) than with OPV (98%). Country specific data were not provided. The experience with current and previous rotavirus vaccines provides several important insights relevant for understanding the potential impact of OPV on rotavirus vaccination. The immune response to the first dose of rotavirus vaccination given concomitantly with the first dose of OPV has almost
always been lower than when vaccine was given without OPV, indicating interference with immune response selleckchem to rotavirus vaccination by OPV. However, a review of the older rotavirus vaccines (i.e., not in current use) suggest that OPV’s negative effect on the first dose of rotavirus vaccination has generally been overcome by administration of subsequent rotavirus vaccine doses , so that comparable immune responses were seen after the full vaccine series among infants receiving vaccine with or without OPV. The three-doses of RotaTeq® are to be given with the routine EPI schedule, which is at 2, 4, and 6 months in the Americas, but at somewhat younger ages of 6, 10, and 14 weeks in Africa and Asia. For the two-doses of Rotarix™, the WHO recommended that the vaccine should be given with the first two doses of the EPI schedule at 6 and 10 weeks of age . The interference from OPV is likely to have a greater negative impact on efficacy of and rotavirus vaccine
during the first EPI visit at 6 weeks of age, when circulating maternal antibodies are also high and are known to also interfere with vaccine take , compared to the second and third EPI visits at 10 and 14 weeks of age. Indeed, an earlier immunogenicity study in South Africa demonstrated better immune responses after two doses of the monovalent rotavirus vaccine, RIX4144, at 10 and 14 weeks of age compared to 6 and 10 weeks of age . Therefore, more evaluations are needed in Asia and Africa to assess the efficacy of Rotarix™ when administered at the WHO-recommended 6–10 week schedule compared to alternative schedules such as 10–14 or perhaps 3 doses at 6–10–14 weeks of age. The key question is whether the impact of OPV on the immune response to rotavirus vaccines translates to a reduced protective efficacy, as measured immune responses to rotavirus vaccination do not necessarily correlate with efficacy.