A Systematic Review of Studies that Measure Parental Vaccine Attitudes and Beliefs in Childhood Vaccination

"Further work is needed to incorporate moral foundations, other feelings and attitudes and beliefs and trust into a single model of vaccination behaviour and test its robustness."

Attitudes and beliefs affect vaccine acceptance, which is an important predictor of vaccine uptake. A range of questionnaires have been developed and tested for measuring vaccination attitudes and beliefs. This study examined how parental attitudes and beliefs towards childhood vaccination were measured globally through a systematic review of the literature.

The study included quantitative studies that used tools to measure parental vaccine attitudes and beliefs, published between January 2012 and May 2018. A total of 116 studies met the inclusion criteria, of which 99 used a cross-sectional study design, 5 used a case control study design, 4 used a pre-post study design, and 8 used mixed methods study designs. Thirty-four countries were represented in the included studies; the countries in which the highest number of studies were conducted were the United States (US), Canada, and the United Kingdom (UK).

The most commonly used standard questionnaire was the Parent Attitudes about Childhood Vaccines (PACV) Survey Tool (n=7), which has been validated in two different settings and been shown to identify vaccine-hesitant parents. In some studies, the PACV questions were adapted to match the local context or study population, such as in Malaysia and for expectant US parents. A variety of theoretical frameworks were used to inform the design of the questionnaires used in the studies. The most common was the Health Belief Model (HBM), which was explicitly stated as having been used to inform the questions in 25 (19.0%) studies, followed by the Theory of Planned Behaviour, which was used in 5 (4.3%) studies.

Of the 38 studies that asked about vaccination intentions for one or more antigens, 16 (13.8%) of these specifically asked about whether parents would have their children vaccinated for all childhood vaccines. The percentages in these studies ranged from 75% in a study involving 200 parents in the US to 98% in a study involving 54 parents in Canada.

Reflecting on the findings, the researchers note that a large number of studies did not report using a validated questionnaire. Of those who did, there were significant differences in the way in which questionnaires were developed and the questions asked in each of the studies. As there is no agreed-upon gold standard survey instrument, a wide range of sources were used for development, resulting in heterogeneity of questionnaires. This makes synthesis or comparison of findings a challenge.

According to the researchers, the use of standardised questions on vaccine attitudes and beliefs should be encouraged. Large international surveys based on a standardised set of questions may be useful for providing international comparisons with additional context-specific questions. To consider the local context, qualitative investigations could supplement broad-based quantitative knowledge from surveys.

However, the speed with which information and misinformation can spread via the internet may outpace our ability to measure and report on attitudes and beliefs using current survey methods, which are time and resource intensive. Due to the time lag involved, using these methods may limit the ability to support the rapid design of evidence-informed and localised interventions for debunking or mitigating the impact of misinformation. In this context, the researchers conclude, "The use of a standard set of validated questions should be encouraged in this area of study to identify, track, and monitor longitudinal trends using quality data."