Immunity to Intranasal Challenge with Rubella Virus Two Years after Vaccination: Comparison of Three Vaccines

Abstract

The persistence of antibodies was studied in 143 women two years after postpartum rubella vaccination. In addition, the effect of intranasal revaccination with the RA 27/3 strain was studied in 99 women after two years. All women had responded to primary immunization with the development of hemagglutinationinhibiting antibodies. Intranasal revaccination resulted in a significant rise in titer of hemagglutination-inhibiting antibodies in 9% of the vaccinees who received the RA 27/3 strain compared with 53% and 24% of those who received the Cendehill and HPV-77 DE-5 vaccines, respectively. The difference between the response in the RA 27/3 group and that in the Cendehill group was statistically significant (P > 0.001), as was the difference between the response of the latter group and that of the HPV-77 DE-5 group (0.03 < P < 0.01). The susceptibility to intranasal challenge was found to be related to low levels of serum hemagglutinationinhibiting antibodies. The titers of hemagglutination-inhibiting antibody were well maintained during the follow-up period, but three of the 52 Cendehill vaccinees had titers of > 1:10 after two years.