[A serological study on the immunization schedule at first dose of domestic BRD II strain rubella vaccine].

In order to develop a valid immunization schedule on the initial vaccination at different age of domestic BRD II strain rubella vaccine, a total number of 268 children at the age of 6 to 18 months from Yantai city of Shandong Province, China were selected for the serological study on hemagglutination inhibition (HI) antibody level against rubella from August to October, 1995. The results showed that the negative rates of HI antibody among children of 6, 7, 8, 9, 12 and 18 month olds before inoculation with rubella vaccine were 100.00%, 95.56%, 93.02%, 96.36%, 97.96% and 93.94% with geometric mean titers (GMTs) 0.00, 1.17, 1.21, 1.12, 1.07 and 1.13, respectively. After one month of immunization with rubella vaccine, the positive rates and GMTs of HI antibody were 97.67%, 95.56% 97.67%, 98.18%, 97.96%, 96.67% and 110.17, 197.02, 155.32, 177.63, 192.92, 142.17, respectively. There was no significant difference on immuno-response to rubella vaccine in children regardless the previous titers. Taking these results together with the current vaccine immunization schedule for expanded programme on immunization (EPI) in China into consideration, the author recommended that the immunization schedule at first vaccination for BRD II strain rubella vaccine should be started at 8 month olds.