Validation of the Vaccination Confidence Scale: A Brief Measure to Identify Parents at Risk for Refusing Adolescent Vaccines

Objective To validate a brief measure of vaccination confidence using a large, nationally representative sample of parents. Methods We analyzed weighted data from 9018 parents who completed the 2010 National Immunization Survey-Teen, an annual, population-based telephone survey. Parents reported on the immunization history of a 13- to 17-year-old child in their households for vaccines including tetanus, diphtheria, and acellular pertussis (Tdap), meningococcal, and human papillomavirus vaccines. For each vaccine, separate logistic regression models assessed associations between parents' mean scores on the 8-item Vaccination Confidence Scale and vaccine refusal, vaccine delay, and vaccination status. We repeated analyses for the scale's 4-item short form. Results One quarter of parents (24%) reported refusal of any vaccine, with refusal of specific vaccines ranging from 21% for human papillomavirus to 2% for Tdap. Using the full 8-item scale, vaccination confidence was negatively associated with measures of vaccine refusal and positively associated with measures of vaccination status. For example, refusal of any vaccine was more common among parents whose scale scores were medium (odds ratio, 2.08; 95% confidence interval, 1.75-2.47) or low (odds ratio, 4.61; 95% confidence interval, 3.51-6.05) versus high. For the 4-item short form, scores were also consistently associated with vaccine refusal and vaccination status. Vaccination confidence was inconsistently associated with vaccine delay. Conclusions The Vaccination Confidence Scale shows promise as a tool for identifying parents at risk for refusing adolescent vaccines. The scale's short form appears to offer comparable performance.