The coronavirus disease (COVID-19) pandemic has been a continuous global health threat since the first identification of the disease in December 2019, resulting in more than 418 million cumulative cases and 5 million deaths worldwide as of 18 February 2022 [1
At present, there are no specific antiviral therapies for COVID-19, and vaccination against COVID-19 is considered to be one of the most cost-effective health interventions for the prevention and control of the pandemic [4
]. Internationally, many countries are attempting to accelerate the research and development of COVID-19 vaccines. As of 18 February 2022, there have been more than 195 vaccines in pre-clinical development, with 144 vaccines in clinical development [7
]. Currently, many types of COVID-19 vaccines, including mRNA, recombinant protein, adenovirus vector and inactivated virus vaccines have been approved in various countries. The results of clinical trials and real-world studies have demonstrated that the candidate vaccines are safe and effective [8
]. However, with the development of the pandemic, inaccurate information about COVID-19, such as information underestimating the severity of the pandemic or ignoring the detrimental effects of the pandemic, has become widespread [9
]. Meanwhile, there have been numerous reports of problems after vaccination published on the Internet, such as muscle soreness, fever and even immune system diseases [10
]. These findings have led to increasing public doubts about the safety and reliability of the vaccine, all of which may affect expectations regarding vaccination [11
]. Vaccine hesitancy may be responsible for the low COVID-19 vaccination rate. The Strategic Advisory Group of Experts (SAGE) defined vaccine hesitancy as a “delay in acceptance or refusal of vaccines despite availability of vaccination services” [12
]. Communication and media environments are potential drivers of vaccine hesitancy [13
]. Social media is connecting people while rapidly spreading, sharing and acquiring large-scale knowledge about COVID-19. This knowledge may increase awareness of COVID-19 vaccines, shed light on their efficacy and safety and reduce vaccine hesitancy. However, social media has created an “infodemic”, an overload of information both online and offline, where too much information (some of it right, some of it wrong) makes it hard to find reliable sources [14
]. False information and rumors about COVID-19 vaccination have emerged on social media, with people unable to tell whether the information is real or not, leading to people hesitating about vaccination.
Thus, to control COVID-19, it is very important to understand the public’s willingness to vaccinate and the associated factors, which can serve as an early warning system to prompt necessary measures to prevent the decline of vaccine acceptance and trust. Many studies have begun to focus on the factors that may affect people’s willingness to be vaccinated. For example, Robinson and colleagues found that younger, less educated, lower-income and ethnic minority populations were less likely to be vaccinated [15
]. Taylor et al. [16
] reported that vaccination attitudes are closely related to cognitions regarding the pandemic, such as the perceived risk of COVID-19 and the perceived severity of SARS-CoV-2. Qian Zhou et al. [17
] reported that risk perception regarding the COVID-19 pandemic was significantly associated with acceptance of vaccination. Therefore, the current study aimed to understand cognitions regarding COVID-19 and SARS-CoV-2, the relationship between them and to identify factors causing vaccine hesitancy or acceptance. Clarifying this issue is critical for updating vaccination strategies and immunization programs against COVID-19 in future.
2. Materials and Methods
2.1. Study Design, Population and Sampling
A cross-sectional online survey was conducted using convenience sampling and snowball sampling strategies from September to October 2020. The survey was conducted online using the largest online survey platform in China: Wen Juan Xing. This platform is equivalent to Qualtrics and SurveyMonkey and provides online questionnaire design and survey functions for enterprises, research institutions and individuals. Participants aged over 18 could fill in the questionnaire anonymously. The online survey link was disseminated via QQ (https://im.qq.com/index
accessed on 18 February 2022) and WeChat (https://weixin.qq.com/
accessed on 18 February 2022), on which personal information and public websites can be shared with family members, friends and colleagues and forwarded to others by participants. According to the sample size formula
required for the cross-sectional investigation, the willingness rate of COVID-19 vaccine vaccination reported in literature p
≈ 80% was taken, as well as the significance level α
= 0.05 and the absolute allowable error d
= 2.5%. This survey used non-random sampling, where Deff
= 2 was taken as the design effect. Considering the sample loss caused by unpredictable factors, the sample size was increased by about 10% on the basis of the above estimated sample size, and the minimum sample size required was calculated as n
= 2164. In order to ensure the validity of online questionnaires, 2171 valid questionnaires were obtained by excluding 12 invalid questionnaires that did not meet the requirements.
In the current study, the questionnaire was designed by consulting domestic and foreign literature on vaccination intention. We referred to well-studied questionnaires with a high degree of credibility and validity in the relevant literature, combined with information related to COVID-19 infection, the COVID-19 vaccine and the social and cultural background in China. The questionnaire included the following contents: socio-demographic characteristics, knowledge of COVID-19, risk perception of COVID-19, willingness regarding emergency vaccination, the COVID-19 vaccine, views on the safety and protective effects of the COVID-19 vaccine and the factors affecting vaccination acceptance. To clarify potential problems with this questionnaire, several small sample pre-surveys were conducted before the formal survey, and the questionnaire was modified and improved on the basis of the results of returned questionnaires and any shortcomings identified via respondents’ feedback.
The variables measured in this study included socio-demographic characteristics, such as gender, age, residence, education level, monthly income and other general demographic variables. Knowledge about COVID-19 was divided into four dimensions: COVID-19 related knowledge, with 10 items; transmission mode of COVID-19, with seven items; symptoms after COVID-19 infection, with 8 items; and preventive measures for COVID-19 infection, with 9 items. Respondents rated the statements as “true”, “false”, or “unclear”. Risk perception of COVID-19 was examined with two questions: “Do you think the domestic COVID-19 epidemic will break out again in autumn and winter this year” and “Do you think you will be infected with COVID-19 this autumn and winter”. Each question was scored on a scale of 0–10 based on the probability perceived by the sample population, with 0 indicating impossible and 10 indicating very likely. The higher the score, the higher the perceived risk of COVID-19. Opinions on the safety and protective effects of COVID-19 vaccines were assessed with two questions: “What is your opinion regarding the safety of COVID-19 vaccines currently entering phase III clinical trials in China?” and “What is your opinion regarding the protective effects of COVID-19 vaccines currently entering phase III clinical trials in China?” Respondents answered using a scale of 0 to 100, with 0 indicating unsafe or ineffective, and 100 indicating very safe or effective. The Likert Scale 6 was adopted for assessing respondents’ willingness to receive the COVID-19 vaccine for emergency use, and the score range was 0–10, with 0–1 indicating definitely unwilling, 2–3 indicating probably unwilling, 4–5 indicating somewhat unwilling, 6–7 indicating somewhat willing, 8–9 indicating willing and 10 indicating definitely willing.
2.4. Statistical Analysis
Microsoft Excel 2019 software was used to organize the data, and SPSS 21.0 software was used for statistical analysis. We used the following descriptive analysis procedure: (1) describing the general demographic characteristics of the respondents; (2) describing the scores of respondents’ knowledge and opinions on COVID-19, scoring the four dimensions, respectively; awarding points for correct answers and not for incorrect or “don’t know” answers, and converting each of the four dimensions to a score of 10; (3) views on the safety and protective effects of the COVID-19 vaccine were transformed to a 10-point system. We described the willingness of emergency vaccination in terms of proportion and frequency; scores of 0–5 were combined with willing vaccination, and scores of 6–10 were combined with unwilling vaccination. The influencing factors of vaccination intention were analyzed using chi-square tests. After univariate analysis, multivariate logistic regression (Forward: LR) was used to conduct multivariate analysis to further explore the influencing factors of the change of COVID-19 vaccine vaccination intention and mitigate the impact of confounding factors.
In this analysis, the inclusion criterion was α = 0.05, and the exclusion criterion was α = 0.10. The odds ratio (OR) and 95% confidence interval (CI) for “willing” versus “unwilling” were calculated. The test level was α = 0.05.
The survey in the current study adopted the Likert Scale 6, on the basis of recommended scoring methods for examining vaccine hesitancy, unlike other surveys that used “willing”, “uncertain” or “unwilling” for classification selection. The data obtained using the Likert Scale were likely to be closer to the real willingness to receive the COVID-19 vaccine following authorization under Emergency Use Administration (EUA) [18
]. According to the current survey results, respondents who were definitely unwilling, probably unwilling, somewhat unwilling, somewhat willing, willing and definitely willing to be vaccinated accounted for 9%, 6.8%, 14.4%, 14.8%, 20.1% and 35% of the sample, respectively. Respondents who were willing (somewhat willing, willing and definitely willing) to take the vaccine accounted for 70% of the sample, which was slightly higher than the rate of vaccination intention (68%) reported by Nguyen et al. [19
], and approached the rate reported in a global study in which 71.5% of respondents reported that they would take a vaccine if it were proven to be safe and effective [20
]. The current results indicated that respondents who recognized the safety and protective effects of the COVID-19 vaccine were more willing to get vaccinated (p
< 0.001). The main reasons for respondents’ reluctance to get vaccinated were concerns about the efficacy of the vaccine and its potential side effects. Thus, the efficacy and safety of the vaccine were the main factors influencing vaccination willingness, which is consistent with the findings of previous studies [20
]. An absence of concerns about vaccine safety and increased awareness regarding vaccine side effects have been reported to make people more likely to take the vaccine [18
The univariate analysis results revealed that men, older people, those with a low education level, those with a high COVID-19-related knowledge level and those with a high COVID-19 risk awareness level had a higher rate of vaccination willingness (p
< 0.001). The current results revealed that the older the respondents were, the higher their willingness to be vaccinated against COVID-19, which was consistent with the findings reported by Lazarus et al. [20
]. Compared with younger age groups, older people face a greater risk from various pathogenic microorganisms because of the deterioration of bodily function and poor immune function. For infectious pathogens, older people are more likely to experience serious illness, with higher case fatality rates [24
]. Because people in older age groups are more susceptible to serious COVID-19 infections and death, an increased fear of disease in this group has been reported to lead to favorable attitudes toward COVID-19 vaccines [22
]. In addition, because older people tend to receive vaccine information through official channels such as television and radio, they are less likely to be exposed to false news, contributing to the higher likelihood of vaccine acceptance. The current results revealed that men exhibited a higher rate of willingness to be vaccinated against COVID-19 compared with women, which is consistent with previous studies reporting higher rates of influenza vaccination among men [25
]. This may be because men have a higher perception of disease risk compared with women. A previous study reported that the case fatality rate of COVID-19 in men (4.7%) was higher than that in women (2.8%) [27
]. We found that highly educated groups were significantly less willing to be vaccinated for emergency use of COVID-19 vaccines. This may be because more educated individuals receive more information from social networks and various channels and have greater concerns about the effectiveness and side effects of COVID-19 vaccines, affecting their willingness to be vaccinated. Some previous studies of influenza vaccination reported similar results [28
]. On the basis of the transmission characteristics of SARS-CoV-2, the public’s awareness of COVID-19 is important for the prevention of disease and control of the epidemic. Investigation of knowledge and attitudes related to COVID-19 can be helpful for clarifying the level of public awareness, which can inform approaches for the prevention and control of the epidemic. Many cognitive factors contribute to people’s health protection behavior during epidemics, including risk cognition and susceptibility cognition. Other cognitive factors, including the accurate understanding of the mode of virus transmission and cognitions regarding the behavior for effectively reducing the risk of infection, will also have a positive impact on people’s health protection behavior. On the contrary, unclear information and negative attitudes may lead to pain and panic during an epidemic [30
]. The current survey findings revealed that the respondents had substantial knowledge about COVID-19, but the level of accuracy regarding the transmission route and prevention measures of COVID-19 was relatively low. A high percentage of respondents incorrectly believed that there are specific drugs for treating COVID-19. Respondents had relatively high accuracy in judging the more common modes of transmission of SARS-CoV-2, but a low level of awareness of evidence that indirect contact can also transmit COVID-19. The accuracy rate for judging whether “eating garlic” and “taking antibiotics” can effectively prevent COVID-19 was low. A previous survey conducted in 19 countries reported that knowledge significantly affects precautionary measures through the effectiveness of belief, and had a direct effect on attitudes [32
]. The current results also revealed that respondents with high risk awareness exhibited greater willingness to be vaccinated, which is consistent with a previous study [33
]. Another study reported that a high level of knowledge was significantly associated with more positive attitudes and perceptions [34
]. Thus, it is important to raise public awareness of COVID-19.
Emerging evidence suggests that both exposure to misinformation about COVID-19 [9
] and public concern regarding the safety of vaccines may be contributing to the observed decline in the intention to be vaccinated [36
]. This highlights the need for measures to address public acceptability, trust and concern over the safety and benefits of approved vaccines [37
Media platforms should actively fulfill their public responsibilities, carry out science popularization in a targeted way and enable scientific and rational voices to guide the public to raise awareness about COVID-19. However, the authenticity and effectiveness of information disseminated by various we-media should be guaranteed, and the leakage of false and inflammatory information should be avoided. Media platforms can set up targeted publicity campaigns for different groups in the population to promote their access to health knowledge and create knowledge bases of different depths to meet the needs of different groups. The dangers of SARS-CoV-2 and the need for vaccination should be actively promoted during vaccine promotion efforts. Confirmation of the effectiveness of the vaccine by authoritative sources, advice from medical staff, and promotion of the effectiveness of the vaccine by official media can all motivate the public to choose vaccination [32
]. After the vaccine is available on the market, government departments and relevant media should publish vaccine information scientifically and objectively, alongside professional advice from the Center for Disease Control and medical staff, which will improve the public’s confidence in vaccines and their willingness to get vaccinated against COVID-19. To increase the urgency of vaccination and enhance the awareness of the necessity of COVID-19 vaccination, media platforms should actively guide and educate the public. The government is an important factor in the awareness and practice of COVID-19 vaccination, and its attitude towards COVID-19 vaccination has a direct impact on the vaccination rate of the public. The government should disseminate accurate information through health publicity and education to promote rational understanding of vaccines, and to actively promote vaccination.
The current survey involved several limitations. Convenience sampling was adopted in the study, but random sampling was not performed, potentially affecting the representativeness of the study sample. Due to the fact that the participants in our study came from an area that was not affected severely by COVID-19, the findings in this study are not generalizable for residents who live in other areas in China. Future studies should recruit a more representative and larger participant pool. The network questionnaire survey was self-reported and may involve some information bias. This questionnaire was administered from September to October 2020, at which time the vaccination policy was markedly different from the current vaccination policy. At present, the nationwide free vaccination campaign in China is progressing steadily, and most COVID-19 vaccines have been conditionally marketed. Because our study assessed respondents’ willingness to be vaccinated when the vaccine is authorized under EUA, the results may not reflect the true willingness to be vaccinated after marketing. In the context of changing global epidemics and clinical advances in COVID-19 vaccines, public perception and demand for COVID-19 vaccines are also changing. Thus, it will be necessary to investigate the public’s willingness to receive vaccinations at different periods during the COVID-19 pandemic.