Failed rubella immunization in adults: association with immunologic and virological abnormalities.

Immunologic and virological studies were performed in 13 adults (12 women and one man) who failed to seroconvert (as shown by rubella hemagglutination-inhibition [HAI] techniques) after single or repeated courses of HPV-77 DE/5 or RA 27/3 rubella virus vaccine. Immunologic sensitization to rubella virus was assessed from six months to eight years (mean, 3.0 years) after the last course of rubella virus vaccine by using HAI, enzyme-linked immunosorbent assay (ELISA), single radial hemolysis (SRH), neutralization, and virus-specific lymphoproliferative techniques. Despite HAI seronegativity, 11 of 13 subjects demonstrated significant sensitization to rubella virus proteins, as indicated by ELISA (10 of 13), neutralization (9 of 11), SRH (4 of 11), and rubella lymphocyte stimulation techniques (9 of 13). In addition, rubella virus was isolated from three individuals by using cocultivation techniques with peripheral blood mononuclear cells. Failed rubella immunization in adults may have more significance than previously recognized in view of altered patterns of virus-specific immunity and the association of this failure with the rubella virus carrier state.