subject citizens of China who have been vaccinated; this was due to three reasons. First, China has been studying the COVID-19 vaccine since March 2020. In June 2020, the country started its first clinical trial of the COVID-19 vaccine. In addition, China officially joined the COVID-19 Vaccine Global Access in October 2020 and began administering COVID-19 vaccinations at the end of 2020 [3]. In this sense, China was one of the world’s leading countries in the development of the COVID-19 vaccine; therefore, we expected to obtain high-quality data from this country. Second, as of July 7, 2021, the number of COVID-19 vaccinations in China has exceeded 1.32 billion doses [3], making data collection in this country optimal for obtaining sufficient and effective samples. Third, the Chinese government adopted the principle of voluntary rather than compulsory vaccination during the process of COVID-19 vaccinations. Each Chinese citizen can choose whether or not to vaccinate according to his or her preferences; in this respect, the policy environment of China meets the basic requirements for continuous vaccination as outlined in this research. Measures In this study, we designed 32 measurement items to measure the 12 variables in the theoretical model. The scale was designed as a 7-point Likert scale in which “1” represented a measure of strongly disagreement and “7” denoted strongly agreement. All items are shown in Table 1. The content of each item was designed with reference to prior valid measures. We refined the survey contents of the scale to obtain high-quality data. Throughout the investigation, all items were conducted in Chinese. Page 9/22 Table 1 Specific measurement items of the scale Variables Items References Outcome expectancy (OE) OE1: If I get vaccinated, I will feel healthier. [14] OE2: If I get vaccinated, I will feel better mentally. OE3: If I get vaccinated, I will have fewer health problems. Risk perception (RP) RP1: I am concerned about the vaccine efficacy. [36] RP2: I am concerned about the vaccine side effects. RP3: I am concerned about the vaccine rigor of testing. RP4: I am concerned that I may be allergic to the vaccine. Perceived self-efficacy (PS) PS1: I am certain that I can get vaccinated, even if I have to mobilize myself. [4] PS2: I am certain that I can get vaccinated, even if it is difficult. Social positive cues (SPC) SPC1: I will get vaccinated when the doctor recommends it. [36] SPC2: I will get vaccinated when vaccination becomes popular. SPC3: I will get vaccinated when I know enough about vaccine. Vaccine hesitancy (VH) Confidence (CF) CF1: I think the vaccine is not safe. [13] CF2: I think the vaccine is not effective. Complacency (CP) CP1: I think the vaccine is not important. CP2: I think the vaccine is not necessary. Convenience (CV) CV1: I think the vaccine is not convenient. CV2: I think the vaccine is not free. Vaccination intention (VI) VI1: I intend to get all doses of the vaccine during the vaccination period. [37] VI2: I will try to get all doses of the vaccine during the vaccination period. VI3: I plan to get all doses of the vaccine during the vaccination period. Vaccination behavior (VB) VB1: I often get vaccinated during the vaccination period. [38] Page 10/22 Variables Items References VB2: I get all doses of the vaccine during the vaccination period. Satisfactory (SAT) SAT1: Overall, I am satisfied with the vaccine. [39] SAT2: The vaccine I am currently getting meets my expectations. SAT3: I am very pleased with my experience with getting vaccinated. Continuous vaccination (CVN) CVN1: I am likely to continue to get vaccinated in the future. [39] CVN2: I intend to consistently get vaccinated in the future. CVN3: I intend to continue getting vaccinated rather than discontinue the vaccine. Perceived usefulness (PU) PU1: I think that vaccine is useful for my life. [39] PU2: Getting vaccinated improves my health. PU3: Getting vaccinated helps me conveniently perform many tasks. Data collection A pilot survey was deployed to evaluate whether the scale was suitable for studying vaccine adoption. The results of the analysis showed that the scale was suitable for studying continuous vaccination. In addition, due to the effects of missing values, we used only “gender”, “age”, “education” and “province” as survey variables in our investigation of personal attribute information. The formal investigation was based on Chinese samples. Given the feasibility and practical operability of surveys, we posted our questionnaires on the Sojump website (http://www.sojump.com/), a specialized online survey system in China similar to Qualtrics.com or SurveyMonkey.com in the United States. We selected registered members of Sojump as our target population. The website currently has over 60 million registered members who are located in various provinces across China. An advertisement for the survey was posted for one week on public forums. To improve the quality of our data, we charged five Chinese yuan for each respondent to participate. Participation was completely anonymous. Regardless of whether someone chose to participate, there was no risk of loss. To protect respondents’ privacy, “gender” and “province” were set as the nominal variables, while “age” and “education” were set as ordinal variables. The entire investigation period lasted one month (from May 10, 2021, to June 9, 2021). We applied the following screening item: Have you been