The relationship between parent attitudes about childhood vaccines survey scores and future child immunization status: a validation study.

IMPORTANCE Acceptance of childhood vaccinations is waning, amplifying interest in developing and testing interventions that address parental barriers to immunization acceptance. OBJECTIVE To determine the predictive validity and test-retest reliability of the Parent Attitudes About Childhood Vaccines survey (PACV), a recently developed measure of vaccine hesitancy. DESIGN, SETTING, AND PARTICIPANTS Prospective cohort of English-speaking parents of children aged 2 months and born from July 10 through December 10, 2010, who belonged to an integrated health care delivery system based in Seattle and who returned a completed baseline PACV. Parents who completed a follow-up survey 8 weeks later were included in the reliability analysis. Parents who remained continuous members in the delivery system until their child was 19 months old were included in the validity analysis. EXPOSURE The PACV, scored on a scale of 0 to 100 (100 indicates high vaccine hesitancy). MAIN OUTCOMES AND MEASURES Child's immunization status as measured by the percentage of days underimmunized from birth to 19 months of age. RESULTS Four hundred thirty-seven parents completed the baseline PACV (response rate, 50.5%), and 220 (66.5%) completed the follow-up survey. Of the 437 parents who completed a baseline survey, 310 (70.9%) maintained continuous enrollment. Compared with parents who scored less than 50, parents who scored 50 to 69 on the survey had children who were underimmunized for 8.3% (95% CI, 3.6%-12.8%) more days from birth to 19 months of age; those who scored 70 to 100, 46.8% (40.3%-53.3%) more days. Baseline and 8-week follow-up PACV scores were highly concordant (ρ = 0.844). CONCLUSIONS AND RELEVANCE Scores on the PACV predict childhood immunization status and have high reliability. Our results should be validated in different geographic and demographic samples of parents.