ANTIBODY RESPONSE OF SCHOOL CHILDREN TO LIVE ATTENUATED RUBELLA VIRUS VACCINES AS MEASURED WITH VARIOUS SEROLOGIC METHODS

Furesz, J. (Virus Laboratories, CCDC, Dept. Nat. Health and Welfare, Ottawa, K1A OK9, Ontario, Canada). Antibody response of school children to live attenuated rubella virus vaccines as measured with various serologic methods. Am J Epidemiol 95: 536–541, 1972.—The antibody response of 6- to 9-year-old children to HPV-77DE5 vaccine (Meruvax) and 10- to 14-year-old children to Cendehill vaccine (Cendevax) has been measured with the hemagglutination-inhibition (HI), micro serum neutralization (SN) and complement-fixation tests. Specific antibodies to rubella virus were detected in 94.6%, 94.6% and 64% of the 92 susceptible children 6 weeks after vaccination (Meruvax) with the HI, SN and complement-fixation tests, respectively. Of the 89 susceptible children who received the Cendevax vaccine, 98.9% showed seroconversion in the HI test. Fifty pairs of these sera were assayed for rubella antibodies also in the SN and complement-fixation tests. SN antibodies were demonstrated in all postvaccination sera and 93.5% of them contained complement-fixing (CF) antibodies. Since CF antibodies could be detected in the majority of postvaccination sera, the previously held view that the complement-fixation test was a reliable method for differentiation in antibody response between attenuated and wild rubella virus strains cannot be justified any more. It has been demonstrated that SN antibody titers in the micro tissue culture assay after the administration of either vaccine were always low, even when the HI titers of these sera were at a high level comparable with those observed after natural infection. In view of this finding and the good correlation found in the sensitivity between the HI and SN tests, the latter assay could be employed as an additional method in cases when the serologic diagnosis in vaccinees or in vaccine contacts is doubtful. The serologic data of this study support the idea that the differences observed in antibody responses to natural rubella infection and to live vaccines are probably quantitative rather than qualitative.