Study explores medical exemptions from school vaccination requirements across states

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.

Fast Facts:

1. Rates of medical exemptions from kindergarten immunization requirements were higher in states where these exemptions are easier to obtain and in states that allow permanent compared to temporary exemptions.
2. The appropriate use of medical exemptions from immunization requirements is important in maintaining community or herd immunity and protecting public health.
3. Improper medical exemptions from school vaccination requirements can result in serious and life-threatening infections in children and others who truly cannot be vaccinated due to underlying conditions.

Founded in 1904, The Journal of Infectious Diseases is the premier publication in the Western Hemisphere for original research on the pathogenesis, diagnosis, and treatment of infectious diseases; on the microbes that cause them; and on disorders of host immune mechanisms. Articles in JID include research results from microbiology, immunology, epidemiology, and related disciplines. JID is published under the auspices of the Infectious Diseases Society of America (IDSA). Based in Arlington, Va., IDSA is a professional society representing more than 9,000 physicians and scientists who specialize in infectious diseases. For more information, visit www.idsociety.org