Maintenance of high-avidity rubella-specific IgG antibody and titres in recent HIV seroconvertors and in patients progressing to the AIDS-related complex and AIDS.

The avidity (functional affinity) and titre of rubella-specific IgG antibodies were examined in sequential and cross-sectional sera from 38 adult HIV-infected patients, whose HIV status ranged from pre- and recent HIV seroconversion to the AIDS-related complex (ARC) and AIDS, in order to determine whether a preexisting mature antibody response to rubella is maintained or if there is a need for rubella (re)vaccination. Thirty-five patients were already rubella-seropositive and one became rubella-seropositive during the time in which sera were collected. Although the avidity of rubella-specific IgG was higher in HIV-positive patients than in their age-and sex-matched HIV-negative counterparts, the difference was not significant. The titres of this antibody, however, were significantly higher in the HIV-positive patients. No significant decrease in antibody avidity or titre were seen in sequential sera from individual HIV-positive patients except when the titres in pre-HIV-seroconversion sera were compared with the titres in sera from patients with AIDS, where a significant decrease was observed. This would suggest that preexisting humoral immunity to rubella in HIV-infected patients is not compromised with HIV disease progression and there should be no need to revaccinate.