Addressing Vaccine Hesitancy: Validating the PACV Survey for Croatian Parents

"...findings highlight the significance of these results in the context of vaccine hesitancy and the tool's potential for future use in similar populations."

Vaccine-hesitant parents exhibit a range of behaviours, such as refusing some vaccines, delaying their children's vaccinations, or accepting vaccinations with uncertainty. According to a 2016 population study, 11% of Croatian parents refused all mandatory vaccines for their children, while 20% agreed to have their children vaccinated with some mandatory vaccines. The Parent Attitudes about Childhood Vaccines (PACV) Survey is designed to detect vaccine-hesitant parents. The objective of this study was to adapt and translate the original PACV questionnaire from English to Croatian language and to examine its psychometrics. By validating the questionnaire specifically for the Croatian population, the researchers hope to use it to effectively assess the attitudes, beliefs, and concerns of Croatian parents about childhood vaccination, providing insights into the specific factors contributing to vaccine hesitancy in this context.

Originally, the PACV was designed to measure four content domains, including immunisation behaviour, beliefs about vaccine safety and efficacy, attitudes about vaccine mandates, and trust. So far, several validation studies, with factor analysis included, have been performed worldwide. Based on the data provided, it seems that the factor structure of the PACV questionnaire may differ based on geographical and cultural influences. Although a three-factor structure was preferred in most validation studies of PACV ("General attitudes", "Safety and efficacy", and "Behavior"), there are several exemptions regarding the number of factors identified and the distribution of items across specific factors - which shows the impact of cultural and regional context.

A cross-sectional study with 1,814 Croatian parents was conducted using the PACV survey, translated using a double-back translation method. The majority of participants (95.6%) women. This high percentage of mothers was expected, as women are generally more willing to participate in health-related surveys than men, are more involved in child health, and, in Croatia, tend to take on a greater role in child-rearing and caregiving than fathers.

Selected findings:
 

• Nearly half of the respondents (48.4%) had a total PACV score of 50 or higher, classifying them as vaccine-hesitant parents, although only 41.6% of them considered themselves to be hesitant.
• More than half of the respondents (54.7%) did not want their children to receive all recommended vaccines.
• 43.4% of respondents had delayed vaccinating their child at least once for reasons other than illness or allergies, and 32% had decided not to vaccinate their child at least once, even though the child did not have any allergies or illnesses.
• 51.4% of the respondents were not sure that following the vaccination schedule was good for their child, and 44.4% believed that children receive more vaccines than are good for them.
• Over 60% of respondents were concerned that vaccines are not safe and that their children could suffer serious consequences from them, and they think it would be better if fewer vaccines were administered at the same time.
• Nevertheless, most respondents trust their child's doctor and consider it important to be able to discuss vaccination openly with their child's doctor.

A large study involving 18 European countries, including Croatia, reported that 62% of surveyed parents in Croatia in 2019 did not consider themselves hesitant about vaccinating their children. The data from the present study indicate a slightly lower percentage of non-hesitant parents, possibly suggesting increased vaccine mistrust and hesitancy among parents in recent years. The reasons for these increased rates of vaccine hesitancy in Croatia can vary. In Croatia, childhood vaccination is mandatory and affects school enrollment, but even if parents do vaccinate their children, that does not mean they are supporting the vaccination programme. Some studies have shown that parents can still express serious distrust and fear and be hesitant although they vaccinated their children. Mandatory vaccination can also lead some parents to refuse vaccination due to a sense of coercion. In addition, in Croatia, there is a significant presence of misinformation spread through social media, which can lead to concerns about vaccine safety and side effects. These and other factors, coupled with specific parental beliefs, such as skepticism about the number and timing of vaccines, reflect the complex landscape influencing vaccine hesitancy in Croatia.

The psychometrics of the PACV questionnaire were examined, including content validity, dimensionality, construct validity, discriminant validity, and reliability. Confirmatory factor analysis (CFA) assessed the original model's validity, but the original model fit poorly, prompting exploratory factor analysis (EFA) to identify latent factors.

The Croatian version of PACV consists of 15 items framed within five distinct factors: "Safety", "Schedule", "Attitudes", "Behavior", and "Trust". Subsequent CFA confirmed this model with acceptable to good fit indices. Discriminant validity was also confirmed. Reliability analyses indicated high internal consistency, with total Cronbach's alpha at 0.926 and McDonald's omega at 0.931.

Future research could conduct a deeper analysis that includes a more representative sample and that examines the influence of broader social factors, such as the impact of media, social networks, and misinformation on vaccine hesitancy. 

In conclusion, this study found that the adapted PACV is a valid and reliable tool for identifying vaccine hesitancy among Croatian parents. "It can aid in addressing vaccine hesitancy and in developing effective strategies and policies to increase childhood vaccination coverage and rebuild trust in vaccines in Croatia." This study revealed high vaccine hesitancy among Croatian parents, emphasising the need for targeted interventions to rebuild trust in healthcare systems and vaccination programmes.