NCPA - National Center for Policy Analysis

Excess Immunization Of Children

March 9, 2000

One fifth of U.S. children receive at least one unnecessary, duplicative vaccine dose by the time they are three years old, researchers report in the Journal of the American Medical Association. This excess immunization costs more than $26 million per year, they estimate.

R. Monina Klevens, of the Centers for Disease Control and Prevention, and colleagues base their conclusion on data from the U.S. 1997 National Immunization Survey. Parents of 32,742 children, ages 19 to 35 months, were interviewed about their children's immunization history with the diphtheria-tetanus-pertussis, poliovirus, measles-mumps-rubella and other vaccines.

For 22,806 of the children, vaccination histories were also collected from health care professionals.

  • Twenty-one percent of the children had received at least one extra vaccination, and 31 percent were under-immunized with at least one vaccine.
  • The researchers found that the frequency of extra immunization was less than 5 percent for each vaccine, except that the frequency for the poliovirus vaccine was 14.1 percent.
  • The strongest risk factors for extra shots were having more than one immunization provider and having multiple types of providers, such as both private and public health departments.

The investigators say that a conservative estimate of the annual costs incurred is $26.5 million. They suggest that "improvements in immunization record keeping and sharing practices may help reduce extraimmunization," adding that "it is particularly important that extra doses of diphtheria and tetanus toxoids be avoided to prevent potential adverse events."

However, an accompanying editorial notes that "it is important to recognize that the risk of withholding vaccinations still far outweighs concerns about cost or the small added risk of adverse events associated with extraimmunization."

Source: Suzanne M. Feikema, et al., "Extraimmunization Among U.S. Children," Journal of the American Medical Association, March 8, 2000.


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