US Department of Health and Human Services calls for assessment of immunization schedule

The first meeting of the Committee on Assessment of Studies of Health Outcomes Related to the Recommended Childhood Immunization Schedule was held in February in Washington, DC, at the Pew Charitable Trust.

This meeting launched an effort to examine the recommended childhood immunization schedule, what's known about its health effects, and how they can be studied. The first discussion made it clear that those questions are full of complexities.

The Institute of Medicine (IOM) study, requested by the Department of Health and Human Services (HHS), is also charged with identifying potential research approaches, methodologies, and study designs that could inform this question.

Ellenberg said doing a trial could raise a "huge ethical issue" because "the recommended schedules [were] developed to confer protection against disease at the earliest time that an adequate immune response can be mounted." She also said that assigning some children to a schedule that delays or skips vaccines would increase their risk of disease.

Ellen Wright Clayton, JD, MD, who chaired the panel for an IOM study on adverse effects of vaccines, said, "I would hypothesize that any of the studies that you look at . . . are actually systematically going to underestimate the adverse effects on health outcomes of nonstandard immunization."

That's because "the children who are immunized protect the ones who aren't," Clayton said.

Gary Freed, MD, MPH, of the University of Michigan School of Public Health, told the committee that physicians have difficulty assimilating and disseminating the existing information in effective, efficient mechanisms. Different types of parents have different information demands, he said, depending on variations in parts of the country and certain racial and ethnic groups.

Freed also said that most physicians and parents are unaware of surveillance efforts such as the Vaccine Adverse Event Reporting System and the Vaccine Safety Data Link, including the significant amount of information they have and their successes in getting reports of adverse events.

"Much of that information is impenetrable both to the physicians and to parents," Freed said. It would be helpful to have information that is vaccine and series specific, facts about safety of alternative schedules and their consequences, and aid for physicians in framing the concept of risk versus disease.

The study report, to be drafted by a committee of 14 experts from around the country, may be published next year.