Discriminant validity.

Background
Sporadic outbreaks of COVID-19 remain a threat to public healthcare, especially if vaccination levels do not improve. As Malaysia begins its transition into the endemic phase, it is essential to identify the key determinants of COVID-19 vaccination intention amongst the pockets of the population who are still hesitant. Therefore, focusing on a sample of individuals who did not register for the COVID-19 vaccination, the current study integrated two widely used frameworks in the public health domain—the health belief model (HBM) and the theory of reasoned action (TRA)—to examine the inter-relationships of the predictors of vaccination intention amongst these individuals.
Methodology
Primary data from 117 respondents who did not register for the COVID-19 vaccination were collected using self-administered questionnaires to capture predictors of vaccination intention amongst individuals in a Malaysian context. The partial least squares structural equation modeling (PLS-SEM) technique was used to analyze the data.
Results
Subjective norms and attitude play key mediating roles between the HBM factors and vaccination intention amongst the unregistered respondents. In particular, subjective norms mediate the relationship between cues to action and vaccination intention, highlighting the significance of important others to influence unregistered individuals who are already exposed to information from mass media and interpersonal discussions regarding vaccines. Trust, perceived susceptibility, and perceived benefits indirectly influence vaccination intention through attitude, indicating that one’s attitude is vital in promoting behavioral change.
Conclusion
This study showed that the behavioral factors could help understand the reasons for vaccine refusal or acceptance, and shape and improve health interventions, particularly among the vaccine-hesitant group in a developing country. Therefore, policymakers and key stakeholders can develop effective strategies or interventions to encourage vaccination amongst the unvaccinated for future health pandemics by targeting subjective norms and attitude.

背景
新型冠状病毒肺炎（COVID-19）的散发病例仍对公共卫生体系构成威胁，若疫苗接种率未能提升，这一威胁将更为严峻。随着马来西亚逐步过渡至疫情常态化阶段，明确仍存在疫苗犹豫的人群中，影响其新冠疫苗接种意愿的关键决定因素至关重要。为此，本研究以未登记接种新冠疫苗的人群为研究样本，整合公共卫生领域两大经典框架——健康信念模型（Health Belief Model, HBM）与理性行为理论（Theory of Reasoned Action, TRA），探究该群体中疫苗接种意愿各预测因子间的内在关联。
研究方法
本研究通过自填式问卷收集了117名未登记接种新冠疫苗的受访者的一手数据，以捕捉马来西亚语境下该群体疫苗接种意愿的预测因子。本研究采用偏最小二乘结构方程模型（Partial Least Squares Structural Equation Modeling, PLS-SEM）方法对数据进行分析。
研究结果
在未登记接种的受访者群体中，主观规范与态度在健康信念模型（HBM）因子与疫苗接种意愿之间发挥关键中介作用。具体而言，主观规范在行动线索与疫苗接种意愿之间起到中介效应，这凸显了重要他人对已接触大众媒体及人际间疫苗相关讨论的未接种登记人群的影响作用。信任、感知易感性与感知获益通过态度间接影响疫苗接种意愿，表明个体态度对推动行为转变具有重要意义。
研究结论
本研究证实，行为因子有助于理解疫苗接种拒绝或接受的背后动因，并可用于优化健康干预措施，针对发展中国家的疫苗犹豫群体尤为如此。因此，政策制定者与核心利益相关方可通过聚焦主观规范与态度维度，制定有效策略或干预措施，以在未来的公共卫生疫情中推动未接种人群完成疫苗接种。