Updated Theory of Planned Behavior in Predicting Parents' Intentions to Vaccinate Their Sons in Elementary School against Human Papillomavirus

Abstract

Purpose: This study was to determine how attitude, subjective norm, and perceived behavioral control (PBC) were related to parents' intentions to vaccinate their sons in elementary school against human papillomavirus (HPV), applying the updated theory of planned behavior. Two hypotheses were examined: PBC would moderate the relationship of attitude to intention and subjective norm to intention, respectively. Methods: This was a cross-sectional study with 231 participants recruited in November, 2018. Inclusion criteria for the participants were parents with 5th-6th grade boys in elementary schools. The moderation effects of the hypotheses were analyzed using the PROCESS macro for SPSS. Results: PBC significantly moderated the relationship of attitude to intention on HPV vaccination. The simple effect of attitude to intention was significant under three different levels of the PBC (low, moderate, and high), but the magnitudes of the relationships were not homogeneous. The magnitude of the relationship between attitude and intention was the lowest for the parents with the low level of the PBC. In the relationship of subjective norm to intention on HPV vaccination, the moderating effect of the PBC was not supported. Subjective norm and PBC directly predicted the intention on HPV vaccination. Conclusion: In order to promote the parents' intentions to vaccinate their sons in elementary school against HPV, we need a program that can improve parents' attitude, subjective norm, and PBC, requiring special attention to the parents with the low PBC.