December 10, 1999

Investigators to track impact of new vaccines

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Dr. Kathryn Edwards

Investigators to track impact of new vaccines

Dr. Marie Griffin

Dr. Marie Griffin

Two grants from the Centers for Disease Control and Prevention (CDC) will enable Vanderbilt University Medical Center investigators to monitor the impact of new vaccines on childhood immunization rates and disease.

Dr. Kathryn M. Edwards, professor of Pediatrics, and Dr. Marie R. Griffin, professor of Preventive Medicine, will use the CDC funding to establish databases that contain information about immunizations, doctor visits, and disease for a large population of children. With this computerized information, they will track the effects of introducing new vaccines.

"We now have a very crowded childhood immunization schedule," Griffin said. "We need to be able to measure what happens when a new vaccine is introduced — are children having more doctor's visits, are they getting more shots at one visit, or are some vaccines being neglected?"

In addition to evaluating immunization data, Edwards and Griffin will use the databases to monitor the burden of disease.

The CDC grants are timely, as two new vaccines move toward being recommended for routine administration to all children. One is a pneumococcal vaccine to prevent meningitis, bloodstream infections, pneumonia, and even ear infections. The other is a nose-drop influenza vaccine. Both have been studied in clinical trials at Vanderbilt.

"From the clinical trials, we know a lot about these vaccines and that they are effective in preventing disease," Griffin said. "But once they're out in general use, we need to be able to determine how they work in the real world. Are they being used appropriately and do they prevent disease in a larger population?"

"These grants represent a neat 'marriage' between investigators who have studied the vaccines and investigators who can establish and use databases to look at rates of disease," Edwards said. "They will allow us to put our strengths in vaccine and database development together to answer important questions about the impact of disease."

To establish databases, Edwards and Griffin will use information from two populations of children — those enrolled in TennCare and those treated by the Cumberland Pediatric Foundation, a network of 300 primary care and academic pediatricians. In addition, they will link information from the Tennessee State Immunization Registry, a record of all immunizations administered by public health departments.

These overlapping populations will constitute the New Vaccine Surveillance Network, which the investigators will use to evaluate the impact of newly licensed vaccines on overall immunization rates and on the burden of disease. For example, the incidence of antibiotic prescriptions and chest x-rays can be compared before and after introduction of the new pneumococcal vaccine.

"With the databases we develop, we'll be able to determine the rates of disease prior to a new vaccine being introduced, in the transition period when it's beginning to be used, and after it has been fully implemented," Edwards said.

A centralized system containing immunization information will have benefits beyond the studies planned by these grants. Since many children receive immunizations from more than one provider, records are often incomplete. And although the Tennessee State Immunization Registry contains information on immunizations administered by public health departments and TennCare providers, private physicians have not been required to submit this information.

"The ultimate goal of the State Registry is to have information on immunizations for all children in the state. With such a system in place, physicians could access immunization records for any child in Tennessee," Griffin said. "We will be working with the state health department and the private providers to create a system for easy exchange of information.

"There is a whole movement toward computerizing this kind of information, and there are multiple uses for it."

Other investigators participating in the CDC grants include Wayne A. Ray, Ph.D., professor of Preventive Medicine, and Dr. Michael D. Decker, associate professor of Preventive Medicine.