SEX-DIFFERENCES IN THE HUMORAL ANTIBODY-RESPONSE TO LIVE MEASLES-VACCINE IN YOUNG-ADULTS

Background. Following vaccination of children using high-titre live me asles vaccine, excess non-specific mortality was reported, particularl y among females. Since vaccination with live measles virus results in a temporary depression of the immune response to other antigens, the f emale predominance in subsequent non-measles mortality may be due to s ex differences in response to live measles vaccines. Methods, In this study, the immunogenicity of standard titre live Schwarz strain measle s vaccine was examined 2 and 4 weeks post-vaccination in 223 males and 66 female aged 18-20 years in Israel in 1991. Results, Females had hi gher post-vaccination geometric mean titre (GMT) at all levels of pre- vaccination titres at both 2 and 4 weeks. Furthermore, after controlli ng for differences in pre-vaccination titres, overall the post-vaccina tion GMT for females was about 50% higher than for males (P < 0.001). Conclusions. These findings indicate that females exhibit a stronger h umoral immune response to measles vaccine. Possible sex differences in immunosuppression following measles vaccination should be explored.