Résumé :
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[BDSP. Notice produite par INIST R0xQEVxi. Diffusion soumise à autorisation]. Context. - Measles causes serious morbidity in infants, with the highest risk among those who are 6 to 12 months of age. In the United States, measles vaccine has been given at age 12 to 15 months to minimize interference by passive antibodies and to achieve the high seroprevalence required for herd immunity. Infants of mothers with vaccine-induced immunity may lose passively acquired antibodies before 12 months, leaving them susceptible to measles infection. Objective. - To assess the immunogenicity of measles vaccine in infants younger than 12 months. Design. - Cohort study conducted before and after measles immunization. Setting. - Pediatric clinic in Palo Alto, Calif. Participants. - Infants 6 (n=27), 9 (n=26), and 12 (n=34) months of age were enrolled ; 72 provided both initial and follow-up samples. Main Outcome Measures. - Evaluation of immunogenicity before and 12 weeks after measles vaccination, including measles neutralizing antibody titers, measles-specific T-cell proliferation, and cytokine profiles. Results. - Measles neutralizing antibodies were present before vaccination in 52% (12/23), 35% (7/20), and 0% (0/22) of 6-9-and 12-month-old infants, respectively. In the absence of detectable passive antibodies, geometric mean titers after vaccination were significantly lower in 6-month-old infants compared with 9-month-old infants (27 vs 578, P=01) and 12-month-old infants (27 vs 972, P=001). (...)
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