BACKGROUND:
According to the 2003 National Immunization Survey, Colorado ranked 47th in the nation for 19-35 month old children who were up-to-date (UTD) in their vaccinations, with only 63.0% of children having the required 4+DTaP, 3+Polio, 1MCV, 3+Hib and 3+HepB, and 1+Varicella vaccinations. Low-income children, such as those in Women, Infants, and Children (WIC) programs, were considered especially high-risk for under-immunization.

OBJECTIVE:
A study was conducted to assess and enhance immunization rates among children of WIC clients in three counties in metropolitan Denver.

METHOD:
Four WIC clinics were included in this study. In three clinics, mothers of children aged 2 months to 5 years completed a survey for each eligible child on randomly selected days. At a fourth, smaller clinic, eligible mothers were surveyed every day for a 3-month period. Information was obtained for each mother-child pair on demographic information, insurance, and health care. Immunization records were reviewed, and non-UTD children were referred for vaccination and followed.

RESULT:
A total of 1571 WIC mother-child pairs were surveyed, with a mean participation rate of 81.4%. At baseline, between 63.7% and 74.2% of participating children were found to be UTD with their immunizations in the four clinics. Between 21.7% and 31.7% of children whose mothers reported they were UTD were in fact lacking immunizations, mainly DTaP. Non-UTD children were referred for vaccination, raising clinic UTD rates to a range of 78.7% to 84.5%.

CONCLUSION:
Immunization rates for the WIC population in this study were well below the Healthy People 2010 target of 90%. Discrepancies between self-reported and actual UTD status point to the need for improved immunization education for WIC mothers, particularly with regards to DTaP. Linking immunization referrals with WIC clinics can raise immunization rates.

LEARNING OBJECTIVES:
To assess and improve childhood immunization rates in a high-risk population.