Experience with rubella and rubella immunization in institutionalized children

Serial monitoring of rubella hemagglutination-inhibiting antibodies in institutionalized children revealed that 4 of 16 nonvaccinated rubella-susceptible children had developed antibodies and 4 of 29 children immunized with Cendehill rubella vaccine had a fourfold or greater rise in antibody titer during the same 4 year interval. This apparent spread of wild virus occurred within three building with a population estimated to be 91 per cent “immune.” The vaccinees have shown a slight fall in hemagglutination-inhibiting antibody titers over the four years, and both the vaccines and naturally immune children who experienced the “booster” response had titers lower than the others. These observations cast doubt on the ability of “herd immunity” to prevent the spread of wild rubella virus.