Exemptors from vaccination also increase risk for some vaccinated children
CHICAGO -- Children who are exempt from immunization for religious or philosophical reasons have a higher risk of measles and pertussis, according to an article in the December 27 issue of The Journal of the American Medical Association. Parents and public health personnel should be aware of the risks involved in not vaccinating children and the potential impact on the community, the authors add.
Daniel R. Feikin, M.D., M.S.P.H., of the Centers for Disease Control and Prevention, Atlanta, and colleagues conducted a population-based, retrospective cohort study to evaluate whether personal exemption from immunization is associated with the risk of measles and pertussis at individual and community levels. They collected data on standardized forms regarding all reported measles and pertussis cases among children aged 3 to 18 in Colorado during 1987-1998.
According to background information cited in the study, 48 states allow exemptions from mandatory vaccination for religious reasons, and 15 states allow philosophical exemptions. Exemptions based on medical grounds are allowed in all states. A recent study showed that the risk of measles infection during 1985-1992 in the United States was, on average, 35 times greater in children with personal exemptions compared with vaccinated children.
In Colorado, the percentage of school-aged children who were unvaccinated as a result of personal exemptions in 1994 was 1.4 percent, more than twice the national average of 0.6 percent.
The authors assessed the relative risk of measles and pertussis among exemptors and vaccinated children, the association between incidence rates among vaccinated children and the frequency of exemptors in Colorado counties, the association between school outbreaks and the frequency of exemptors in schools, and the risk associated with exposure to an exemptor in measles outbreaks.
Contact: Daniel R. Feiken, MD, MSPH
Center for the Advancement of Health