HAPA model, ECM, and VH theory, we produced a theoretical model that explores the impact process of continuous vaccination in COVID-19 and obtained six valuable conclusions. Implications First, perceived self-efficacy has a positive significant impact on vaccination intention, but the effects of outcome expectancy and risk perception on vaccination intention are not significant. This conclusion is not completely consistent with the views in the HAPA model, in which the three variables—that is, outcome expectancy, risk perception, and perceived self-efficacy— are all pre-factors of behavioral intention [4]. However, in the context of COVID-19, the roles of outcome expectancy and risk perception have not been demonstrated. We believe that one possible reason for this result is that this study is an empirical analysis carried out in China; at present, China is one of the few countries where the global epidemic is well controlled, so in this region, the public’s concern about COVID-19 is not as serious as Page 16/22 when the virus first broke out. Conversely, the public does not feel safe about the newly developed COVID19 vaccine. In other words, vaccination may not be the safest health behavior in the minds of the Chinese public. Therefore, in the context of COVID-19, only the effect of perceived self-efficacy on behavioral intention has been proven. Second, social positive cues have a positive significant influence on vaccination intention. This conclusion is similar to the evidence obtained from existing studies [21, 22]. In an environment where vaccination is questioned by the public at this stage, reliable knowledge, suggestions, and information are important guidelines for determining the intention of public behavior. The results of our analysis show that social positive cues are important elements that affect the public’s behavioral intentions. However, combining the third conclusion, based on the values of path coefficient, we conclude that compared with VH, social positive cues have a relatively limited effect on behavioral intention. This also shows that the public still holds, to a certain extent, a variety of concerns about vaccination. Third, VH has a negative significant influence on vaccination intention. This conclusion is consistent with existing studies [13, 24] and illustrates a dilemma for COVID-19 vaccine at this stage. China was one of the first countries in the world to develop the COVID-19 vaccines and has recently exported them; however, due to fewer clinical trials, side effects, effectiveness, and other reasons, the COVID-19 vaccines still have not been fully recognized in the public mind. Although China implements a free vaccination policy for the public, the value of path coefficient shows that the negative impact of VH on vaccination intention is still great. Fourth, vaccination behavior produces a positive significant effect on perceived usefulness and satisfaction, respectively. This conclusion is completely consistent with the views in ECM [5]. According to the first and third conclusions of this study, we can conclude that the public’s recognition of the COVID19 vaccine is not high. However, the empirical analysis results show that when the public is vaccinated, they find that their own expectations can be confirmed. So far, there have been no cases of adverse reactions due to vaccination in China. Moreover, the vaccinated public has a reliable health code, which allows them to more freely and safely enter some public places. The public can not only perceive the usefulness of the vaccine, but also feel satisfied with the vaccination process and experience. This indicates to some extent that the COVID-19 vaccine is not so bad at this stage. Fifth, perceived usefulness exerted a positive significant impact on satisfaction and continuous vaccination, respectively. This conclusion can be used as a supplement to previous research findings [32, 33]. Similar to other vaccines, the public’s perception of the usefulness of the COVID-19 vaccine can not only enhance their satisfaction, but also prompt them to be vaccinated again. Moreover, based on the values of path coefficient, we can see that the positive impact of perceived usefulness is prominent. This explains that the perceived usefulness of the COVID-19 is an important factor affecting public emotions and subsequent behaviors. Sixth, satisfaction has no positive significant influence on continuous vaccination. This conclusion is different from previous research [28, 34], and it indicates the particularity of the COVID-19 vaccine. We Page 17/22 speculate that the main reason for this conclusion is that vaccination is a comprehensive behavior that is affected by various factors such as gender, age, region, culture, and religion. Satisfaction may influence several of these factors, but these impacts are not enough to contribute to continuous vaccination. We did not examine the impact of VH on continuous vaccination in the behavior stage, but based on the factor loadings of the VH variable in the intention stage, we find that the public’s VH mainly focuses on confidence and complacency. In fact, complacency may play a potential role in continuous vaccination. In addition, the present study makes some practical contributions. First, governments of various countries need to strengthen all types of vaccination publicity. In this regard, it is best for relevant departments to publicize the benefits of the health behavior