Understanding the psychosocial determinants of Italian parents' intentions not to vaccinate their children: an extended theory of planned behaviour model.

Objective: This study aimed to identify the psychosocial factors involved in Italian parents' intentions not to vaccinate their children. For this purpose, we used an extended version of the Theory of Planned Behaviour, which included both proximal and distal factors influencing intention not to vaccinate children.

Design: Participants included 447 Italian parents, each completed an online questionnaire, which measured intention not to vaccinate children, attitude toward not vaccinating, subjective norms, perceived behavioural control, anticipated regret, negative attitude toward vaccines, risk perception, trust in healthcare institutions, trust in science and religious morality.

Results: Results showed that attitude toward not vaccinating was strongly associated with intention not to vaccinate children. Furthermore, attitude toward not vaccinating was associated with negative attitude toward vaccines, which in turn was affected by all the distal factors considered (risk perception, trust in healthcare institutions, trust in science, religious morality). Finally, negative attitude toward vaccines fully mediated the effect of the distal factors on attitude toward not vaccinating children.

Conclusion: These findings provide support for the validity of the proposed extended TPB model in explaining parents' intention not to vaccinate children. Theoretical and practical implications, in terms of understanding and promoting vaccination behaviour, are discussed.