Studies on the reactogenicity and immunogenicity of the BRD-2 and RA27/3 live attenuated rubella vaccines

A study to compare the reactogenicity and immunogenicity of the BRD-2 and RA27/3 rubella vaccine strains was conducted in GuangXi, China in 1982. Ninety eight susceptible children between two and six years of age, with haemagglutination inhibition (HI) antibody titres of less than 10, were inoculated with RA27/3 vaccine strain. A similar group of 103 children were inoculated with BRD-2 vaccine strain; 110 uninoculated children served as a control group. The percentages of children who had fever reactions were 30.09% for RA27/3, 20.04% for BRD-2, and 24.50% for the uninoculated group. Neither vaccine evoked a high fever reaction. For both vaccines, the seroconversion rates estimated 42 days after immunization were 100%. The geometric mean titre of HI antibody was 144.4 +/- 2.04 for recipients of RA27/3, and 116.1 +/- 2.0 for those vaccinated with BRD-2. The rate of excretion of virus from the nose and throat was 26.67% for the recipients of RA27/3 and 23.08% for those who received BRD-2. No vaccine virus was isolated from the uninoculated susceptibles who were in close contact with the vaccinated children. Furthermore, the latter group remained seronegative when tested after 42 days of contact with the vaccinated. Hence, it appears that both RA27/3 and BRD-2 vaccine viruses have no capacity for being transmitted to unvaccinated contacts. In susceptible adolescents immunized with the BRD-2 vaccine viruses have no capacity for being transmitted to unvaccinated contacts. In susceptible adolescents immunized with the BRD-2 vaccine strain, a mild febrile reaction was observed.(ABSTRACT TRUNCATED AT 250 WORDS)