SIMULTANEOUS ADMINISTRATION OF ORAL RHESUS-HUMAN REASSORTANT TETRAVALENT (RRV-TV) ROTAVIRUS VACCINE AND ORAL POLIOVIRUS VACCINE (OPV) IN THAI INFANTS

Rhesus-human reassortant tetravalent (RRV-TV) oral rotavirus vaccine w as given at the same time as oral poliovirus vaccine (OPV) or inactiva ted parenteral poliovirus vaccine (IPV) to Thai infants at 2, 4 and 6 months of age. Sera for rotavirus antibody studies were taken prior to and one month after each vaccination. After the first dose of vaccine at 2 months of age, 37% of the infants receiving rotavirus vaccine wi th IPV but only 10% of those receiving it with OPV showed a seroconver sion by rotavirus IgA ELISA antibody test (p < 0.001). Likewise, neutr alizing antibody seroconversion rates in initially seronegative subjec ts to rhesus rotavirus type 3 (RRV-3) after the first dose of RRV-TV v accine were higher if the vaccine was given with IPV (74%) than if giv en with OPV (39%) (p = 0.0069). After the second and third doses of va ccine, the rotavirus IgA ELISA and RRV-3-neutralizing antibody respons e rates were not different between groups, Development of neutralizing antibodies to human rotavirus serotypes 1, 2 and 4 in the first seven months of life in vaccinees receiving rotavirus vaccine with OPV tend ed to occur at a lower. rate than in those receiving rotavirus vaccine with IPV but the antibody levels were not significantly different at 7 months of age. Poliovirus type 2 and type 3 antibody responses were not different in infants receiving the rotavirus vaccine with OPV as c ompared with infants receiving only OPV. The mean poliovirus type I an tibody level was slightly bur not significantly lower at 5 and 7 month s of age in infants that received both rotavirus vaccine and OPV. Thes e results suggest that OPV is likely to interfere with the take of RRV -TV rotavirus vaccine but the interfering effect can largely be compen sated for by giving multiple doses of RRV-TV vaccine or, possibly, by using a higher-titre rotavirus vaccine. Interference of RRV-TV vaccine with OPV may not pose a significant problem, but further research is required to ascertain that antibody responses to poliovirus type 1 are not affected by RRV-TV especially if a higher-titre vaccine is used.