RESUMO
OBJECTIVES: To study immunogenicity and reactogenicity of indigenously produced MMR vaccine and to assess the booster effect of MMR immunization on measles seroconversion. DESIGN: A longitudinal follow up. SETTING: Hospital based and home follow up, as required. SUBJECTS: 89 children already immunized for measles, between 15 to 24 months of age for immunogenic evaluation and 866 subjects for the reactogenic component. METHODS: Prevaccination and postvaccination samples collected one and four weeks after vaccination were studied by ELISA for IgG and IgM antibodies against the three diseases. A clinical follow up of immunized children was done at 3 days, 7 days, 6 weeks and 6 months after immunization. RESULTS: IgG positivity 4 weeks after immunization rose from 75% to 100% for measles, from 12% to 92% for mumps, and from 13% to 99% for rubella. Only mild side effects including pain and swelling in 37 (4.3%) cases, mild fever in 51 (5.9%) cases, cough in 40 (4.6%) cases and a transient rash in 7 (0.8%) cases were observed. CONCLUSIONS: The indigenously manufactured MMR vaccine has an excellent immunogenicity and low reactogenicity with a booster effect for measles seroconversion in children already immunized for this disease.