The impact of record scattering on the measurement of immunization coverage

BACKGROUND: Lack of a consolidated immunization record may lead to problems with determining individual immunization needs at office visits as well as measuring vaccination coverage levels of a clinician's practice or a community's population. OBJECTIVES: For children with multiple immunization providers- evaluate the difference in coverage levels using data from all responding immunization providers compared with: 1) the most recent immunization provider's records- 2) the first immunization provider's records- and 3) a randomly selected immunization provider's records. Identify characteristics of the most recent provider that may be associated with reporting incomplete immunization histories. METHODS: Data from the 1995 National Immunization Provider Record Check Study (NIPRCS) were used for analysis. The NIPRCS is a provider validation study of the household reported immunization histories of all children 19 to 35 months of age included in the National Health Interview Survey (NHIS). Providers identified by the child's parent during the NHIS interview are mailed a 2-page survey to report all immunizations (type and date) the child received- regardless of the provider who administered the shots- and child's first and most recent visit dates to the practice. RESULTS: Of the 1352 children with provider data- 304 (22%) had received immunizations from more than one provider. Compared with information from all providers and depending on the vaccine- the most recent provider records underestimated coverage by 9.6 to 13.4 percentage points/ the initial provider records underestimated coverage by 15.6 to 34.6 percentage points/ and the randomly selected provider records underestimated coverage by 10.0 to 20.7 percentage points. Public facilities and having an immunization summary sheet in the patient's chart were associated with having complete records. CONCLUSION: Scattered immunization records significantly compromise the ability of clinicians to determine the immunization status of their patients who received immunizations at other sites of health care. Routinely assessing immunization coverage levels at the practice level- implementing a recall system- and developing community-wide immunization registries are some strategies to reduce the problem of scattered immunization records.immunization- assessment- provider validation- record scattering.