Elsevier

Vaccine

Volume 29, Issue 38, 2 September 2011, Pages 6598-6605
Vaccine

Validity and reliability of a survey to identify vaccine-hesitant parents

https://doi.org/10.1016/j.vaccine.2011.06.115Get rights and content

Abstract

Objective

To assess the construct validity and reliability of the Parent Attitudes about Childhood Vaccines survey.

Study Design

Cross-sectional survey of parents of 19–35 month old children in a closed model HMO. We used factor analysis to confirm survey sub-domains and Cronbach's α to determine the internal consistency reliability of sub-domain scales. Construct validity was assessed by linking parental responses to their child's immunization record.

Results

Our response rate was 46% (N = 230). Factor analysis identified 3 factors that explained 70% of the total variance for the 18 survey items. We deleted 3 items that failed to load highly (>.4) on an identified factor, correlated poorly with other items, or had a hesitant response that was not associated with increased under-immunization. Cronbach's α coefficients for the 3 sub-domain scales created by grouping the remaining 15 items were .74, .84, and .74, respectively. Children of parents with survey scores of 50–79 had 14% more days under-immunized from birth to 19 months (95% CI: 8.0, 20.5) than those with parents who scored <50. Scores of ≥80 were associated with 51% more days under-immunized (95% CI: 38.2, 63.4).

Conclusion

The revised survey is a valid and reliable instrument to identify vaccine-hesitant parents.

Highlights

► Vaccine attitude survey tested by linking parent scores to child's vaccine records. ► A higher survey score was associated with more under-immunization. ► The survey is a valid and reliable instrument to identify vaccine-hesitant parents.

Introduction

Parental acceptance of childhood immunizations in the US is eroding [1], [2]. Nearly 12% of parents have refused at least 1 recommended childhood vaccine [3] and there is an increasing number of parents who are filing philosophical exemptions from required childhood vaccines [4]. A group of parents that is important to our understanding of this growing parental immunization resistance are vaccine-hesitant parents (VHPs).

VHPs represent a heterogeneous group of parents who may purposefully delay or choose select vaccines, have moderate concerns about vaccine safety, and yet still want to trust and receive immunization information from their child's provider [5], [6], [7], [8], [9], [10]. This group has become a focus for research aimed at improving parental acceptance of childhood immunizations because their child's provider remains in a position of influence [11], their immunization attitudes are not extreme, and they are a larger group than those who completely reject vaccines [8], [12]. To develop future interventions to increase immunization rates among children, it is critical to have a valid and reliable method for identifying VHPs.

We previously developed a survey—the Parent Attitudes about Childhood Vaccines (PACV) survey—to identify VHPs [13]. Our preliminary evaluation of the PACV demonstrated its face and content validity, but more robust psychometric assessments of the PACV have yet to be done. Our objectives for this study were to (1) use factor analysis to confirm the number of latent constructs of the Parent Attitudes about Childhood Vaccine (PACV) survey, reduce the total number of PACV items, and measure the internal consistency reliability of identified sub-domains; (2) determine the ability of individual PACV items to discriminate between vaccine-hesitant and non-hesitant parents by associating parental item response with their child's immunization status; and (3) determine the construct validity of the revised PACV by examining the association of the total PACV score with a child's immunization status. We hypothesize that higher parental PACV scores will reflect higher vaccine hesitancy by being associated with increased child under-immunization.

Section snippets

Survey sample

The survey sample was selected by simple random sampling from a birth cohort of 19–35 month old singleton children born between April 2007 and August 2008 who had English-speaking parents ≥18 years old and who belonged to a large, integrated, US health care delivery system (Group Health Cooperative (GHC), Seattle, WA). This age range of 19–35 months was chosen because it represented a suitable time to obtain parental perspectives on vaccines as it occurs after the schedule completion of the 15

Survey results

We received 230 completed surveys for a 46% response rate. Most respondents were mothers, parents aged 30 years or older, married, and white (Table 2). While the majority of parents trusted the information they received about immunizations and would want all the recommended childhood immunizations if they had another infant today, 27% of parents reported delaying and 16% reported refusing a recommended immunization for reasons other than illness or allergy (Table 3). In addition, more than half

Discussion

This study evaluated the construct validity and internal consistency reliability of the newly-developed PACV survey. The PACV was designed to specifically identify VHPs since existing immunization surveys that seek to understand immunization hesitancy were not explicitly designed to identify VHPs and therefore potentially lack the precision desired. Furthermore, many existing surveys are limited by their lack of demonstrated construct validity, such as utilizing a confirmatory marker for the

Conclusions

The revised PACV survey is a valid and reliable instrument to identify VHPs. Further work is needed to test the predictive validity of the PACV.

Acknowledgements

This study was funded by the Seattle Children's Center for Clinical and Translational Research Pediatric Pilot Fund Award. We would also like to thank Ben Wilfond, MD and Carolyn Korfiatis for their assistance in revising and editing this manuscript. Dr. Wilfond and Ms. Korfiatis have no real or perceived conflicts of interest to declare.

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