Objectives: We compared the prevalence of measles immunization determined by serology with the prevalence of measles immunization determined by immunization records, and identified factors predictive of measles immunization among a sample of children from two Chicago communities.
Methods: We collected demographic information and blood specimens from a sample of children aged 12-71 months in two Chicago communities at risk for low measles immunization coverage levels. We collected immunization information from provider records, parent-held records, and the statewide immunization registry. We compared evidence of immunization determined by serology with evidence of immunization from these three sources of immunization records.
Results: The sample of children from the two communities had serologic measles immunity levels of 85% and 90%. Significantly fewer children had evidence of immunization by record in both communities (45% and 63%, respectively).
Conclusions: Immunization coverage levels determined using immunization records were significantly lower than immunization coverage determined using serology. A fully populated immunization registry used by all immunization providers could prevent the problems of record loss and scatter.