Vaccination of two virgin-soil (without historical or serological evidence of past infection) populationsof Amazon Indians with RA 27/3 rubella vaccine was followed by fever of >100 F in 10% of the vacinees and by ephemeral arthralgia in 2%. These frequencies are not greaterthan those that have been reported for cosmopolitanpopulations of comparable ages. There was little or no secondary spread of the virus. Titers of hemagglutination-inhibiting antibody to rubella virus were prevalent in a third population of Amazon Indians, who had naturally acquired immunity and were unexposed to reinfection, and did not decline during a period of four to 12 years after infection. Antibody titers in the two virgin-soil populations immunized with RA 27/3 vaccine declined by twofold between four months and two and one-half years after vaccination but, at the end of that period, were not appreciablylower than antibody titers at four years in the naturallyinfected population. All age groups except children underone year of age responded to vaccination equally well.
ASJC Scopus subject areas
- Infectious Diseases
- Immunology and Allergy
- Public Health, Environmental and Occupational Health