Comparing telephone and written surveys to assess local adolescent immunization coverage rates

To identify adolescent hepatitis B coverage levels, a survey was conducted of seventh grade parents in San Diego County, California, using a random digit-dial telephone survey. A written survey was fielded also that was distributed at selected schools. Results were validated using data from a mandated report from all schools. Both survey methods overestimated the proportion completing the hepatitis B series by about 10%. Parents accurately reported immunization shot dates from the child's parent-held immunization shot record on the telephone and written surveys. The written survey, in addition to having a somewhat lower cost, may be useful when focusing on a localized area, whereas the telephone survey permits a more representative sample of a larger county-wide population.