Parental Hesitancy toward Children Vaccination: A Multi-country Psychometric and Predictive Study

"Without validated instruments in specific countries and contexts, it is not possible to conduct reliable and valid research to investigate the factors and determinants of parental vaccine hesitancy."

Parental vaccine hesitancy is a crucial concern for public health due to its close links to vaccination delay, refusal, or denial in children, which ultimately increases their vulnerability to preventable diseases. Considering existing theories, models, and conceptualisations, various measures have been developed and evaluated for assessing vaccine hesitancy. This study aimed to validate one such measure, the Vaccine Hesitancy Scale (VHS), and to investigate the predictors of children's vaccine hesitancy among parents from Australia, China, Iran, and Turkey.

The VHS was originally developed by the SAGE Working Group on Vaccine Hesitancy. It has a validated 2-factor structure: (i) lack of confidence (7 items; e.g., "Childhood vaccines are important for my child's health"), and (ii) risk (2 items; e.g., "New vaccines carry more risks than old vaccines"). The scoring procedure for items in the VHS are rated on a 5-point Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). The current study consisted of 4 versions of the VHS: English (for Australia), Chinese (for China), Persian (for Iran), and Turkish (for Turkey). All versions were checked for cross-cultural equivalence.

This study employed a cross-sectional, questionnaire-based research design. In total, 6,073 parents from Australia (2,734), China (523), Iran (2,447), and Turkey (369) completed an online questionnaire between August 8 2021 and October 1 2021. The content and construct validity of the VHS was assessed. Cronbach's alpha and McDonald's omega were used to assess the scale's internal consistency, composite reliability, and maximal reliability. Multiple linear regression was used to predict parental vaccine hesitancy from gender, social media activity, and perceived financial well-being.

The current study found that a brief measure of parental vaccine hesitancy, when appropriately translated, is able to be used in broadly diverse sociocultural contexts. The VHS showed strong and desirable psychometric properties, including predicted factor structure, strong reliability, metric invariance across country, validity, and expected relationships to self-reported outcomes such as affluence, gender, and social media engagement. (Parental vaccine hesitancy was higher in people who identify as female, more affluent, and more active on social media.) These results align with the original validation study conducted in Canada and another study validating the scale in Guatemala.

In reflecting on the findings, the researchers note that there were far fewer fathers than mothers in 3 of the 4 samples (i.e., 4.2% of respondents in Australia, 35% in China, 17.69% in Iran, and 53.9% in Turkey were fathers). However, it is also true that mothers tend to have more decision-making responsibility for the health and welfare of children than fathers, and it was mothers who were found to have higher vaccine hesitancy. This finding is aligned with the health belief model, which states that gender plays a strong role in determining vaccine acceptance. For example, studies have indicated that Chinese mothers exhibit a greater vaccine hesitancy for their children than fathers due to their concerns regarding vaccine safety and effectiveness.

Another findings of note is that individuals and those with more social media engagement tended to be more hesitant to vaccine their children, which aligns with prior studies. Parents may be confused by misinformation and fake news in the media and on social networks; consequently, they experience fear, stress, and a wide range of behavioural changes. Misinformation may make parents more cautious about vaccines, especially new vaccines.

Among four countries, the vaccine hesitancy score was lower in China, though this difference is not statistically significant. However, it is still notable that effective communication, safe vaccine availability, cultural influences (China's collectivist culture, which emphasises community health and well-being), government initiatives, and past vaccination success have all contributed to lower levels of vaccine hesitancy among parents in China compared to other countries.

The study indicated that lack of confidence in the vaccine and perceived vaccine risk contribute to parental vaccine hesitancy. According to the 3 Cs model (confidence, complacency, and convenience) presented by the SAGE working group, lack of confidence in vaccine safety and effectiveness, as well as low or mistrust of the systems that recommend or provide the vaccine, can determine vaccine hesitancy. Furthermore, the model suggests that hesitancy may occur when parents do not value or perceive a need for vaccination (complacency) or when the vaccine is not accessible and available (convenience).

This study supports broad use of the VHS to evaluate parental vaccine hesitancy as part of an effort to understand and counteract resistance to adoption of vaccines. Applying this scale can provide information for public health authorities to manage vaccine hesitancy among parents. For instance, healthcare providers can use this information to tailor their communication strategies to address the specific concerns of parents and increase vaccine uptake. Health policymakers can take note of the fact that social media can play like a double-edged sword in parental vaccine hesitancy. Consequently, they are encouraged to provide authentic and accurate content that presents explicit information in the right way to the right audience.

In conclusion: "Findings from this study have implications for future research examining vaccine hesitancy....Further studies are needed to test the scale's validity and reliability across additional cultural contexts."