This online survey examined the parental COVID-19 vaccination hesitancy among parents of children aged 5–18 years in Thailand. Most of the respondents were parents who hold the right to make a final decision regarding their child’s vaccination. They probably had a high acceptance level of the COVID-19 vaccination, since 96.7% of them had completed the vaccine program, and the average number of the vaccines they received was around 3 shots which included the initial and booster doses.
Even though their children were living in an outbreak area and there were senior or at-risk family members, our findings revealed that 58% of Thai parents had moderate to extremely high levels of PVh. This result was in line with earlier studies conducted in other countries, such as Turkey , Japan , Italy  and Saudi Arabia [23,24,25]. The percentages of PVh in such countries had been reported as high as 52.4–72.2%. Issues regarding confidence in the vaccine efficacy and safety, quality uncertainty, and lack of adequate available information were cited as the contributing factors to the high level of PVh in those studies [15, 16, 22, 23]. Although some recent studies conducted in the United States [26, 27], Malaysia , and South Korea  found that PVh prevalences were considerably lower than our finding (15–28.9%), the above contributing factors of PVh were still indicated [26,27,28].
Previous refusal to receive the COVID-19 vaccine for themselves and completing the initial COVID-19 vaccination were associated with higher and lower PVh, respectively. Those results indicated that the direct experience of the parents with their COVID-19 vaccination was one of the key factors influencing PVh. This hypothesis was supported by previous studies which found that there was an inverse relationship between COVID-19 vaccination history of the parents and PVh [15, 16, 28, 30]. Therefore, a campaign to create a positive attitude towards vaccination for themselves and increase the rate of COVID-19 vaccination among parents, in addition to the promotion of their child’s vaccination should be conducted.
Our study also found that PVh was higher with statistical significance among parents who previously refused any other vaccinations for their children. These parents may have misunderstandings, distrust, excessive fear, and concerns about any vaccination, especially COVID-19 vaccines which had been manufactured by newly invented platforms for an unfamiliar emerging disease . As a result, a history of incomplete vaccination for other diseases of the children may be a screening tool for this group of parents . Special consultation with emphasis on the seriousness of COVID-19 problems in their children and the positive facts and information with proper media should be applied [33,34,35].
In previous studies, parents who had a family member who suffered or died from the disease showed a lower level of PVh . Although those devastating experiences can increase the perceived threat of the disease, the perceived benefits and risks of the vaccine may not be changed. Unsurprisingly, our study did not find a statistical difference in PVh between parents who had or did not have direct experiences with COVID-19. Thus, measures to increase the perceived benefits and decrease the perceived risk of the vaccine should be considered.
Parental subjective norm (SN), perceived behavioral control (PC2), and attitude towards vaccine regarding the unavailability of long-term safety (AV4) were rated with high levels of agreement in our study. However, the multiple regression analysis found that only attitude towards COVID-19, attitude towards COVID-19 vaccine, and parental perceived behavioral control statistically influenced PVh with negative beta values indicating the inverse relationship between those factors and the level of hesitancy. As a result, communication to increase the perceived risk of COVID-19, the perceived benefit of COVID-19 vaccine, and the perceived behavioral control could be the most effective directions to reduce the level of parental COVID-19 hesitancy [36, 37].
To our knowledge, this is the first study to explore the parental COVID-19 vaccine hesitancy in Thailand. Most of the respondents were parents who hold the right to make a final decision regarding their child’s vaccination. The questionnaire was systematically developed in Thai language and tested for its validity and reliability. Therefore, their opinions collected in our study could be highly correlated with the actual decision for their children in the near future.
Although our study was conducted in various living regions which improved the generalizability of our results, some limitations require consideration. First, the study was an online survey. This could be of concern that only parents who were familiar with an online questionnaire and well-equipped can participate in the data collection. Thanks to several national projects of the Thai government such as Thai-Cha-Na (mobile application for tracking COVID-19 contact persons) and Mor-Prompt (mobile application for COVID-19 vaccine services) which most Thai people used in everyday life, nowadays, Thai parents could participate in the online survey without any limitations as aforementioned. Secondly, we conducted this study during a period when the incidence of severe COVID-19 was relatively low. The parental vaccine hesitancy was sensitive to the context of data collection, e.g., outbreak situation and trend, news, rumors on public and social media, national and local policy, as well as local availability of the vaccine. The prevalence of PVh in this study was calculated based on the PVh level at moderate or above. Different cutoff PVh levels for data transformation, such as determining only high and extremely high PVh levels could lead to remarkably different prevalence . Therefore, it is important to use caution when applying the study's findings to other contexts. Further prospective multi-centered studies should be conducted in a larger population to increase the generalizability and address the effective measures to overcome the COVID-19 vaccination hesitancy.