Determination of Up-to-Date Vaccination Status for Preschool-Aged Children: How Accurate Is Manual Assessment Conducted by Paraprofessional Staff?

Abstract

Background. Accurate identification of underimmunized children is needed to determine which children need vaccination. Previous studies have found the accuracy of manually determining the immunization status from a personal vaccination record to be low (<50%). Objective. To determine the accuracy of manual immunization status assessment for preschool-aged children. Subjects and Setting. Children ≤32 months old (n = 21 263) seen over 1 year at 12 women, infants, and children (WIC) sites in San Diego, California. Age at evaluation was between 0 and 24 months. Methods. Paraprofessional immunization specialists conducted manual immunization status assessment using the WIC client's personal vaccination record. Immunization status as recorded in the WIC record was compared with computerized assessment (the gold standard). Measures and Results. For all patient encounters, 29 078 (80%) of 36 368 were assessed correctly; manual assessment outcome was not recorded in the WIC record for 2171 (6%) of encounters. Accuracy varied by WIC site (range: 70%–90%). The sensitivity at correctly identifying an underimmunized child per encounter was 53.6%; the specificity at correctly identifying a fully vaccinated child per encounter was 89.4%. The 3 most common vaccines that were incorrectly assessed in identifying an underimmunized child were Haemophilus influenzae type b (43%), hepatitis B (37%), and diphtheria-tetanus toxoids and (cellular or acellular) pertussis vaccine (24%). Children with no outcome as recorded in the WIC record were 5 times as likely to be up-to-date. Conclusions. Manual immunization assessment was specific but only moderately sensitive at identifying underimmunized children. Thus, many underimmunized children will by missed but only 10% of children will be referred inappropriately.