Identification of childhood vaccine providers in Maryland

The purpose of the study was to compare the utility of an American Medical Association (AMA)-derived list and a Maryland State Department of Health and Mental Hygiene (state)-derived list of potential childhood vaccine providers (CVPs) in identifying true childhood vaccine providers for the Vaccines for Children (VFC) program in Maryland. A telephone survey of a sample of physicians from the two lists was used to determine their status as providers of routine vaccinations to children. Results showed a significant difference between the two lists. The state-derived list was composed of an estimated 60.7% CVPs, whereas the AMA-derived list was composed of an estimated 36.7% CVPs. Using the capture-recapture method, it was estimated that there are about 2077 CVPs in Maryland. Based on this figure, the state-derived list would have identified 71.7% of the state's CVPs, and the AMA-derived list would have identified 59.4%. Using the AMA-derived list would have required contacting approximately 1800 extra providers to identify the additional 350 CVPs (16.8%) not identified in the state-derived list. Accurate, up-to-date lists of providers that include pertinent practice characteristics would enhance the ability to contact specific providers for VFC program enrollment and for other clinical and public health purposes.