Résumé :
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[BDSP. Notice produite par INIST aR0x9obY. Diffusion soumise à autorisation]. Context The risk of vaccine-preventable diseases among children who have philosophical and religious exemptions from immunization has been understudied. Objectives To evaluate whether personal exemption from immunization is associated with risk of measles and pertussis at individual and community levels. Design, Setting, and Participants Population-based, retrospective cohort study using data collected on standardized forms regarding all reported measles and pertussis cases among children aged 3 to 18 years in Colorado during 1987-1998. Main Outcome Measures Relative risk of measles and pertussis among exemptors and vaccinated children ; association between incidence rates among vaccinated children and frequency of exemptors in Colorado counties ; association between school outbreaks and frequency of exemptors in schools ; and risk associated with exposure to an exemptor in measles outbreaks. Results Exemptors were 22.2 times (95% confidence interval [Cl], 15.9-31.1) more likely to acquire measles and 5.9 times (95% CI, 4.2-8.2) more likely to acquire pertussis than vaccinated children. After adjusting for confounders, the frequency of exemptors in a county was associated with the incidence rate of measles (relative risk [RR], 1.6 ; 95% CI, 1.0-2.4) and pertussis (RR, 1.9 ; 95% CI, 1.7-2.1) in vaccinated children. Schools with pertussis outbreaks had more exemptors (mean, 4.3% of students) than schools without outbreaks (1.5% of students ; P=001). (...)
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