Willingness and Uptake of the COVID-19 Testing and Vaccination in Urban China: An Online Cross- Sectional Survey at Early 2021

Suhang Song Columbia university https://orcid.org/0000-0003-1934-632X Shujie Zang Fudan university Liubing Gong Chizhou Center for Disease Prevention and Control Cuilin Xu Yuhuatai Center for Disease Prevention and Control Leesa Lin London School of Hygiene & Tropical Medicine Mark R. Francis Tampere University Zhiyuan Hou (  zyhou@fudan.edu.cn ) Fudan university https://orcid.org/0000-0003-3413-0076


Introduction
Testing and vaccination are two effective measures to mitigate and prevent the transmission of COVID-19. [1][2][3][4] Testing can be used to diagnose COVID-19 by detecting both symptomatic and asymptomatic patients, and can also trace con rmed cases and their close contacts, especially when outbreaks surge. 3,5 The vaccine is expected to play an important role in preventing serious complications from SARS-CoV-2 infections and establishing herd immunity to protect populations from COVID-19 infections. 6   vaccinations are being promoted and scaled up globally; in China, the government enacted the emergency use authorization of COVID-19 vaccines in June 2020 7,8 , and subsequently approved COVID-19 vaccines for general use in December 2020 8, 9 . By the end of March 2020, the peak of the pandemic has passed in China, and the number of new con rmed cases per day rapidly declined to less than 10; most of these cases were imported from abroad. 4,10,11 With COVID-19 resurging in some regions, mass COVID-19 testing and vaccination strategies have been adopted to track and control sporadic outbreaks in many cities such as Beijing 12 and Qingdao 13 . Understanding the willingness to receive and uptake of testing and vaccinations can help design and implement policies to improve access to and acceptance of Page 3/27 COVID-19 tests and vaccination, which is important for effectively promoting pandemic mitigation and prevention strategies.
Previous reviews and empirical studies have focused on estimating the public's willingness to receive and uptake COVID-19 vaccinations. [14][15][16][17][18][19][20][21][22][23][24][25][26] These studies reported that the willingness to vaccinate varied by geographic area [27][28][29][30][31][32][33][34] , socio-demographic characteristics such as age and occupation [29][30][31][35][36][37][38][39][40][41] , and COVID-19 disease and vaccine risk perceptions 29,33,42−47 . A previous survey from China estimated a high willingness to be vaccinated against COVID-19 at the beginning of the pandemic, which declined as the pandemic became normalized due to the reduced perception of COVID-19 risk among the public. 48 Therefore, it is crucial to continue assessing the public's willingness to be vaccinated as their attitudes and risk perceptions are likely to change over time. Disparities in vaccination uptake also need to be further studied, as only a few studies to date have examined the uptake of the COVID-19 vaccination by population characteristics. COVID-19 testing serves as an important complementary measure to prevent and control spikes in SARS-CoV-2 cases, enabling disease diagnosis and tracing the con rmed cases. [49][50][51][52][53][54] Nearly 160 million tests have been performed in China, as of August 6th, 2021. 55 Since studies on the willingness to be tested and actual uptake of COVID-19 tests are scarce, updated estimates can help identify the population subgroups to be targeted by health education interventions in China.
Therefore, we conducted a cross-sectional survey in early 2021, when COVID-19 testing was being used as a primary measure to detect the sporadic outbreaks of SARS-CoV-2 cases 48 and after the COVID-19 vaccine had been o cially approved for use among the general public. 8 This study aims to examine the willingness to receive and uptake of COVID-19 testing and vaccination during the low-risk period of the COVID-19 pandemic in China.

Study Design, Population and Sampling
We conducted an anonymous online cross-sectional survey to collect information on the willingness and uptake of the COVID-19 testing and vaccination and their associated factors among adults aged 18 years and older in two cities (Nanjing and Chizhou) from January 29 to February 4, 2021. Nanjing city in eastern Jiangsu province and Chizhou city in central Anhui province had a gross domestic product (GDP) per capita of CNY 165,681 among 7.10 million population and of CNY 56,217 among 1.62 million population, 56 respectively, making them good representatives of urban China. 57 This study employed snowball sampling to enroll the study participants from four to eight community health centers in each city and from the local Centers for Disease Control and Prevention (CDC). Participants could access the questionnaire through a social media platform, WeChat, which has 1.1 billion active users. Those who completed the survey were encouraged to share a link of the questionnaire and invite their colleagues or friends to participate. To avoid repeated participations, each WeChat account was permitted to ll out the questionnaire only once, and only devices having Internet Protocol addresses were able to submit their responses successfully. It took about 3-5 minutes to complete the self-administered questionnaire and the respondents were given a gift worth roughly CNY 5 after they completed the survey.
In total, 2250 respondents answered the questionnaire independently and provided e-consent for their participation in the survey. Six incomplete questionnaires or questionnaires completed under two minutes were excluded from the analysis, and a total of 2244 respondents were included in the study. The study was approved by the Institutional Review Board of the School of Public Health, Fudan University (IRB#2020-12-0861).

Measures
The self-administered questionnaire was designed based on previous literature and pre-tested among ten respondents, who were excluded from the analysis. The questionnaire included questions on the respondent's socio-demographic characteristics, self-reported health status, awareness of the COVID-19 pandemic, perceived susceptibility and severity of the COVID-19, and willingness to receive and uptake of COVID-19 testing and vaccination.
The outcomes of interest for this study were willingness to receive and uptake of COVID-19 testing and vaccination. Uptake of the COVID-19 test was measured with the question "Have you ever received a COVID-19 test before?" Response options included "already tested," "scheduled," and "haven't been tested or scheduled." Respondents who responded "already tested" or "scheduled" were classi ed into the uptake group, and were further asked their reasons for receiving testing, including community-wide mass testing led by governments, mandatory testing policies for travel, and personal health needs. Respondents who responded "haven't been tested or scheduled" were included in the group who haven't uptake the test. The willingness to receive the COVID-19 test was enquired of all participants with a vepoint Likert scale question, with options including "de nitely willing," ''probably willing," ''not sure," ''probably not willing," and ''de nitely not willing." Responses of "de nitely willing" and ''probably willing" were classi ed as "willing", while those who chose the other three options were assigned as "unwilling". Similar to the uptake of COVID-19 testing, uptake of the COVID-19 vaccine was assessed by whether the participants had been vaccinated against COVID-19; those who chose either "vaccinated" or "scheduled" were added to the "vaccinated" group. Only respondents who had not been vaccinated or not scheduled a COVID-19 vaccination were asked for their willingness to be vaccinated in the future. We assigned participants who had not received or scheduled a vaccination to report their willingness to vaccinate as COVID-19 vaccine needs to be received only one time under the policy during the survey time, while COVID-19 tests need to be received multiple times as needed. However, willingness to continue to be tested still matters for those who had already received a COVID-19 test, and thus needed to be analyzed.
The socio-demographic characteristics collected included location, residency, age, gender, marital status, educational attainment, occupation, and annual income. Location, residency and gender were dichotomized into Nanjing city versus Chizhou city, local residents versus migrants, and male versus female, respectively. Participant's age was categorized into four groups, including 18-25, 26-35, 36-45, ≥46 years old. Marital status was classi ed into single, married and divorced/widow. Educational attainment was grouped into middle school or lower, high school or technical secondary school, junior college, and bachelor's degree or higher. Occupation was categorized into four groups: government agency, service industry, manufacturing industry or agriculture, and others. Annual individual income was grouped into <20,000, 20,000-50,000, 50,000-100,000, 100,000-200,000 and >200,000 Chinese Yuan (CNY). Self-reported health status was assessed on a ve-point Likert scale ranging from very good (1) to very poor (5) and dichotomized into "good" (very good and good) versus "poor" (fair, poor and very poor). Awareness of and perceived susceptibility to COVID-19 were also assessed on a ve-point Likert scalevery high, high, not sure, low, and very low. Respondents who selected the rst two options were classi ed into the "high" group, and those who selected the other three options were assigned to the "low" group. We also asked participants to answer a question on how severe they considered COVID-19 infections to be, "How do you think your symptoms would be if you were infected with COVID-19?", with the following options -severe, moderate, mild, asymptomatic and unsure. These responses were dichotomized into "severe or moderate" versus "mild" (including asymptomatic and unsure).

Statistical Analysis
Descriptive analyses were performed to compare the characteristics of respondents by their willingness to receive and uptake of COVID-19 testing and vaccination. Since all the assessed factors were categorical variables, chi-square tests were used to compare participant' characteristics across the willingness and uptake groups. Multivariate logistic regression models were tted to investigate the factors associated with willingness to receive and uptake of COVID-19 testing and vaccination, with the adjusted odds ratio (aOR) and 95% con dence intervals (CIs) being calculated. The rst and the second models regressed the willingness to receive and uptake of COVID-19 testing with the participant's characteristics, respectively; the third and the fourth models regressed the willingness to receive and uptake of COVID-19 vaccination, respectively. Two-sided P<0.05 indicated signi cance. All analyses were conducted with STATA MP, version 14.0 (StataCorp LLC).   Figure 1B).    Note: Only 1714 participants who haven't received or scheduled a COVID-19 vaccine were asked their willingness. Among them, three participants didn't report their willingness, so the sample size of the vaccination willingness question was limited to 1711. Table 4 presents the factors associated with willingness to receive and uptake of COVID-19 vaccinations in the study sites. Location, age, residence, educational attainment, occupation, self-reported health status, and perceived susceptibility to COVID-19 were signi cantly associated with uptake of COVID-19

Results
vaccination among the survey respondents. Respondents living in Chizhou city, compared to Nanjing city, had a higher uptake rate of COVID-19 vaccination (aOR=1.928, 95% CI=1.488-2.498). Persons aged 46 years or older (aOR=2.012, 95% CI=1.133-3.574), compared to those aged 18-25 years, were more likely to receive or schedule a vaccination, while respondents who had poor perceived health were less likely to receive or schedule a vaccination (aOR=0.540, 95% CI=0.352-0.829). Vaccination uptake among migrants was 1.479 times (95% CI=1.040-2.104) higher than among local residents. Respondents who had educational attainment of junior college or higher and worked in government agencies had higher uptake of COVID-19 vaccinations than those with lower educational attainment or less secure occupations (i.e., industry). The vaccine uptake rate among respondents with high perceived susceptibility to COVID-19 was 3.457 times (95% CI=2.298-5.199) higher than those with low perceived susceptibility. In terms of willingness to receive COVID-19 vaccination, among 1711 respondents who had not been or scheduled a vaccination, more respondents in Chizhou city reported being willing to receive a COVID-19 vaccination than those living in Nanjing city (aOR=1.404, 95% CI=1.110-1.776). Willingness to be vaccinated among respondents with high awareness of and perceived susceptibility to COVID-19 was 3.391 (95% CI=2.285-5.032) and 1.950 (95% CI=1.119-3.398) times higher than those with low awareness and perceived susceptibility, respectively. Other socio-demographic characteristics were not associated with the willingness to receive a COVID-19 vaccination among those who had been vaccinated. in the future. Higher willingness and uptake of COVID-19 testing were associated with more secure occupations, while associations with other socio-demographic characteristics failed to reach statistical signi cance. Being of older age and migrants, having higher educational attainment and working in a secure job were associated with higher uptake of COVID-19 vaccinations, while willingness to receive a vaccination was consistent across the various socio-demographic characteristics assessed. High awareness of and perceived susceptibility to COVID-19 were associated with a higher willingness to receive and uptake COVID-19 testing and vaccination.
Adults in China expressed almost universal willingness to receive COVID-19 testing (95.63%); this rate is higher than populations observed in some other countries, such as Ethiopian and Japan. 58, 59 Regarding the uptake of COVID-19 testing, although some areas had not reported any con rmed cases, over half of respondents reported having received or scheduled a test. Except for occupation, no socio-demographic characteristic was associated with the willingness and uptake of COVID-19 testing, which is consistent with previous studies. 51,60 This indicated the equal willingness and access to COVID-19 testing in China, which may lie in that the Chinese central government and some local governments require healthcare providers to supply the community-wide mass COVID-19 testing without cost-sharing and the testing policies for travel. 61 As a result, we found that the majority of tests were performed due to communitywide mass testing and mandatory testing policies for travel. This nding provides some evidence to support the rollout of mass-testing in urban regions of China. The different uptake rate by occupation may result from the requirements of the employers and government, which may alleviate the anxiety to go back to work in person and be assist in preventing and controlling con rmed cases as well. During the current phase of the pandemic with only sporadic cases, mass testing policies appear to be supported by the public, and continuous implementing these policies could help identify, trace and mitigate con rmed cases even during the low-risk period of the COVID-19 pandemic in China.
As China entered the low-risk period of the COVID-19 pandemic, willingness of the COVID-19 vaccination appears to become relatively low, with only 63.28% of total respondents having received/scheduled or were willing to receive a vaccination, which could pose a challenge to the achievement of herd immunity.
The willingness of COVID-19 vaccination in our study is lower than that in mid-2020 in China Among adults who had not been vaccinated or scheduled a vaccination, socio-demographic characteristics were not associated with willingness to receive a vaccination, indicating the equitable vaccination willingness in China. 21,40 However, the uptake of vaccinations differed by age, residence, educational attainment, and occupation. These disparities are aligned with previous studies in other countries that reported a higher vaccination uptake among older adults and those with higher socioeconomic status. 28,29,31,36 In China, the COVID-19 vaccination is free to the public, 66 and to improve  the access to the vaccination, COVID-19 vaccination units are temporarily set up within the community providing walk-up COVID-19 vaccination 67 . Older adults and migrants face more risk of infecting COVID-19, and are the priority groups of vaccination. Although with equitable willingness, population with a higher level of educational attainment and working in a secure job faced more policy requirements and less barriers to be vaccinated than their counterparts. Most of them work at government agency and formal employment, which usually require the employees to be fully vaccinated before returning to the o ce in person. This policy requirements may contribute to the higher uptake of vaccination among those with a higher level of educational attainment and working in a secure job.
In addition, higher awareness of and perceived susceptibility to COVID-19 were positively associated with the respondent's willingness to receive and uptake the COVID-19 test and vaccination, concurs with data from previous studies that report perceiving a high risk of infections may increase willingness and uptake rates for both testing and vaccination. 29,33,[42][43][44][45][46][47]51,60,68,69 This study is subject to several limitations. First, this study conducted an online survey, which may have resulted in the study groups being more homogenous with respect to certain socio-demographics.
Second, this cross-sectional study just showed associations, instead of causal associations, and did not compare the current rates of willingness to receive and uptake of COVID-19 testing and vaccination with the rates from the active period of the pandemic, and therefore cannot capture trends or the changes in these proportions over time. Last, this study was conducted at the early stage of COVID-19 vaccination rollout. Thus, further research is warranted to assess the public's uptake and willingness to receives COVID-19 test and vaccines in different phases of the pandemic.

Conclusion
Chinese adults expressed almost universal willingness of COVID-19 testing and relatively low willingness of COVID-19 vaccination at the low-risk period of the COVID-19 pandemic. The willingness and uptake of COVID-19 testing and vaccination are independent from their socio-demographic characteristics at most cases.

Declarations
Contribution ZH designed this study.
LG and CX collected the data. SZ conducted literature review. SS analyzed the data and wrote the manuscript. ZH, LL, and MF critically reviewed and revised the manuscript. All authors have seen and approved the nal version of the manuscript. Health, Fudan University for his help in cleaning data. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Declaration of Competing Interest
None.