Follow-up on reubella vaccinations and experience with subclinical reinfection

Abstract

Rubella antibody titers for a group to women vaccinated soon after delivery have decreased slightly after two years. None of their unvaccinated infants—even those who were breast-fed—had any serologic evidence of exposure to rubella virus. Antibody levels have been determined at annual intervals for three years on a group of institutionalized children. The geometric mean titer fell during the second year, then unexpectedly rose during the third year suggesting subclinical reinfections. The incidence of subclinical reinfection was very low among RA 27/3 vaccinees and naturally immune children, but it was 26 per cent among recipients of the Cendehill vaccine. Results suggest that with presently licensed rubella vaccines it is not possible to produce a “herd immunity,” at least, not in an institutional population.