In states where medical exemptions from vaccination requirements for kindergarten students are easier to get, exemption rates are higher, potentially compromising herd immunity and posing a threat to children and others who truly should not be immunized because of underlying conditions, according to a study published in The Journal of Infectious Diseases and now available online. Nationwide in scope, the study found inconsistency among states in standards allowing medical exemptions from school immunization requirements. The investigators concluded that medical exemptions should be monitored and continuously evaluated to ensure they are used appropriately.
In their study, Stephanie Stadlin, MPH, Robert A. Bednarczyk, PhD, and Saad B. Omer, MBBS, MPH, PhD, from the Hubert Department of Global Health at Emory University Rollins School of Public Health in Atlanta, evaluated state medical exemptions from kindergarten entry requirements over seven school years (from 2004-'05 to 2010-'11), which totaled 87,631 medical exemptions nationwide over the period studied. The researchers found that, compared to states with more stringent criteria for getting medical exemptions, states with easier requirements saw a significant increase in these exemptions. Their findings suggest that requiring more accountability of both parents and physicians for granting medical exemptions can be helpful in ensuring that these exemptions are valid and not used as an alternative to non-medical exemptions because they are easier to obtain.
"The appropriate use of medical exemptions is important to maintaining sufficient herd immunity to protect those who should not be vaccinated due to medical contra-indications," said Dr. Omer, the senior investigator of the study. "Medical providers, parents, school officials, and state health officials are responsible for ensuring that medical exemptions are actually medically indicated."
In an accompanying editorial, Daniel A Salmon, PhD, MPH, and Neal Halsey, MD, of the Johns Hopkins Bloomberg School of Public Health in Baltimore, noted that "children with valid medical exemptions need to be protected from exposure to vaccine preventable diseases by insuring high coverage rates among the rest of the population. Granting medical exemptions for invalid medical contraindications may promote unfounded vaccine safety concerns." The researchers' findings, they added, should be useful to those responsible for implementing and enforcing school immunization requirements at the state and local levels.