Determination of up-to-date vaccination status for preschool-aged children: How accurate is manual assessment conducted by paraprofessional staff?

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 v accination record to be low (<50%). Objective. To determine the accuracy of manual immunization status assessme nt for preschool-aged children. Subjects and Setting. Children less than or equal to 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 b etween 0 and 24 months. Methods. Paraprofessional immunization specialists conducted manual immuniz ation status assessment using the WIC client's personal vaccination record. Immunization status as recorded in the WIC record was compared with comput erized assessment (the gold standard). Measures and Results. For all patient encounters, 29 078 (80%) of 36 368 we re assessed correctly; manual assessment outcome was not recorded in the WI C record for 2171 (6%) of encounters. Accuracy varied by WIC site (range: 7 0%-90%). The sensitivity at correctly identifying an underimmunized child p er encounter was 53.6%; the specificity at correctly identifying a fully va ccinated child per encounter was 89.4%. The 3 most common vaccines that wer e incorrectly assessed in identifying an underimmunized child were Haemophi lus influenzae type b (43%), hepatitis B (37%), and diphtheria-tetanus toxo ids and (cellular or acellular) pertussis vaccine (24%). Children with no o utcome as recorded in the WIC record were 5 times as likely to be up-to-dat e. Conclusions. Manual immunization assessment was specific but only moderatel y sensitive at identifying underimmunized children. Thus, many underimmuniz ed children will by missed but only 10% of children will be referred inappr opriately.