Hesitancy toward COVID-19 vaccines among medical students in Southwest China: a cross-sectional study

ABSTRACT

Vaccine hesitancy is an obstacle to COVID-19 vaccination. This study aims to inform the vaccine hesitancy and analyze related factors toward COVID-19 vaccination among medical students in China, so as to provide suggestions for increasing vaccines uptake. An online cross-sectional survey was conducted among medical students in a medical university and a health school. A total of 2,196 valid questionnaires were received. 41.2% vaccine hesitancy was reported among medical students in total. Female (OR = 1.336) and individuals with higher education (OR = 1.724) reported slightly higher vaccine hesitancy. Being in low-risk areas and no need to get vaccinated (OR = 2.285), fear of serious consequences of vaccination (OR = 1.929), being in good health and no need to be vaccinated (OR = 1.891), being concerned about short-term side effects (OR = 1.793) and being concerned that the vaccine was ineffective (OR = 1.694) had higher prevalence of vaccine hesitancy. Those who were believing the specialty of study or work environment made vaccination necessary (OR = 0.378), believing they were susceptible to COVID-19 (OR = 0.411) and the vaccine was free (OR = 0.519) were more willing to get vaccinated. Confidence in vaccines and perceptions of benefits and risk are associated with vaccine hesitancy. It is important to strengthen vaccine health literacy education for medical students and enhance vaccine confidence. Countries need to supervise the public opinions in social media, television broadcasting and other media, so as to ensure the correct orientation of public opinion. Open and transparent evidence-based information is also needed which can help improve the vaccination coverage rate of the public.

Introduction

The global COVID-19 pandemic is still continuing, making a great difference to economy, politics and culture. Through strict and effective public health emergency control measures, China has achieved great success in controlling COVID-19. Herd immunity through universal COVID-19 vaccination is one of the most effective methods to control the epidemic of COVID-19. In order to control the pandemic of COVID-19, many countries including China has been actively developing vaccines since COVID-19 occurred. Since January 2021, China has begun to carry out COVID-19 vaccination among key populations including healthcare workers (HCWs) and later in the general population. Up to now, COVID-19 vaccination has been carrying out orderly in many countries around the world, but vaccine hesitancy has become an obstacle in achieving herd immunity. Vaccine hesitancy is influenced by many factors, which is listed as one of the top 10 threats to global public health by the World Health Organization.¹

The SAGE Working Group defined vaccine hesitancy as the practice of refusing or delaying vaccination despite the availability of vaccination services.² Confidence, complacency and convenience (“3 Cs” model) proposed by the SAGE Working Group are important influencing factors of vaccine hesitancy. Vaccine confidence (e.g., trust in vaccines, trust in healthcare workers and so on) is a global public health issue.^2,3 One study pointed out that HCWs with more vaccines confidence in the safety were more willing to get vaccinated for themselves and their children, and also to commend the vaccine to their patients.⁴ Kwok et al.⁵ found that more confidence and less complacency were associated with stronger COVID-19 vaccination intention. The study indicated that complacency (perceived the disease as low risk) was also associated with influenza vaccine vaccination. Furthermore, vaccination convenience (e.g., availability, affordability and geographical accessibility of vaccines so on) is also an important factor.²

Previous studies^6,7 indicated that when assuming 2019-nCoV reproductive number (R0) is 3 and the vaccine is 100% effective, the incidence of COVID-19 infection begins to decline only when at least 67% of the population gets vaccinated. According to China’s official data, up to April 11, 2021, China reported that a total of 167.343 million doses of COVID-19 vaccine were taken. However, due to the large cardinal number of the population in China, the uptake rate of COVID-19 vaccine is still very low, far from the coverage needed to achieve herd immunity. In China, routine clinical novitiate and internship are required in medical students. Medical students being in clinical novitiate, internship, or standardized training are usually in direct contact with patients and have a great risk of COVID-19 infection. Medical students are an important population for COVID-19 vaccination like other HCWs, whose vaccination’ attitudes toward COVID-19 vaccines could influence the public’ vaccination decision.⁸ Given the importance of vaccination among medical students, it is important to understand their attitudes toward COVID-19 vaccination. This study aims to inform the vaccine hesitancy and related factors among medical students through a cross-sectional survey, so as to provide information and suggestions for COVID-19 vaccination campaigns.

Material and methods

Study design and population

An online cross-sectional survey was conducted among medical students in a medical university and a health school in Luzhou, China. Convenience sampling were used. Inclusion criteria: medical students (Majors: Nursing, Pharmaceutics, Rehabilitation Technology and so on), all grades (from first grade to fifth grade), education level (Technical secondary school education and higher vocational school education, Undergraduate and graduate education), be able to fill in the questionnaire, volunteer to participate in this study and give informed consent.

Measure

The SAGE Working Group on Vaccine Hesitancy proposed 3 C model of vaccine hesitancy which the influence factors of vaccine hesitancy were classified into three categories: confidence, complacency and convenience.² We compiled a questionnaire based on the 3 C model of vaccine hesitancy. The questionnaire included basic demographic information (gender, age, region, grade, specialty and education.), vaccination intention, confidence, complacency, and accessibility and convenience of COVID-19 vaccination services. Considering the urgency of COVID-19 vaccination research, we invited 5 experts working in public health and infectious disease research to conduct questionnaire consultation. After two rounds of expert consultation, the final questionnaire was formed. The scale level content validity index, S-CVI/Ave was 1.00 based on the five experts in China. We conducted a pre-survey among 107 medical students, and 107 valid questionnaires were collected. Medical students were at age of 15–22 and 81.7% were females. The online platform shows that the completion time of a questionnaire is 6–10 minutes, within the acceptable time range of the research subjects. Study subjects reported that the questionnaire items were easy to understand and the online self-administered method was acceptable. Based on the pre-survey data, the reliability of the questionnaire was analyzed. The main contents of the questionnaire (confidence, complacency and service convenience and accessible of COVID-19 vaccine) were assessed by 5-point Likert scale. The 5-point Likert scale (strongly disagree, agree, unsure, agree, strongly agree) were divided into three categories: disagree, unsure, and agree. The Cronbach’s α coefficient of the questionnaire is 0.882 which is a ‘reliable’ level.⁹

To measure vaccine hesitancy, participants were firstly asked “Have you been vaccinated against COVID-19?” The answers included “Yes and No.” Those who had not been vaccinated were asked again “would you like to take the COVID-19 vaccine if it is available now?.” The response options included “Yes, No and Undecided.” The population was divided into two groups (“Vaccine Hesitancy” and “Not Vaccine hesitancy”). With reference to the definition of vaccine hesitancy and related research,^2,10 we define “Vaccine Hesitancy” as those who were undecided and unwilling to be vaccinated. Those who have been vaccinated and would like to get vaccinated were classified as “Not Vaccine Hesitancy.”

Data collection

The questionnaires were collected from March 15 to March 30, 2021, which was powered by www.wjx.cn. With the consent and support of the administrators and teachers of the health school, the online questionnaires were distributed to different classes for students to fill out the questionnaires voluntarily. Meanwhile, medical students were invited on site to fill in the questionnaire online.

Ethical consideration

Based on the principle of anonymity and informed consent of the participants, data was collected. This study was approved by the Affiliated Hospital of Southwest Medical University (Ethics Approval ID.: KY2021076).

Statistical analysis

SPSS 21.0 was used for statistical analysis. The influencing factors for vaccine hesitancy were firstly identified by univariate analysis, and then the multivariate analysis was performed by binary logistic regression. P < .05 indicates statistically significant.

Results

A total of 2196 medical students with an average age of 17.66 ± 2.25 years were investigated. The demographic characteristics of the participants are shown in Table A1. 81.7% participants were females. Urban students accounted for 25.5%, and rural students accounted for 74.5%. Technical secondary school and higher vocational school education, undergraduate and graduate education accounted for 69% and 31%, respectively. Grade one, grade two, grade three, grade four and above accounted for 45.1%, 41.7%, 11.2%, 2% respectively. Medical students were mainly from nursing (64.4%) and pharmaceutics majors (15.9%). There were diverse ways to obtain information about COVID-19 vaccine, including mainly WeChat, QQ, Weibo and other social networks (82.5%), television broadcasting (77.6%), and healthcare personnel (65.3%).

Eighty-three medical students (3.8%) had taken the COVID-19 vaccine, which were divided into “Not Vaccine Hesitancy.” Among those who did not receive the COVID-19 vaccine (n = 2113), the number of medical students would like to be vaccinated against COVID-19 was 1209, accounting for 57.2%. Therefore, the total number of “Not Vaccine hesitancy” was 1292, accounting for 58.8% among all medical students. Those reporting that they were unwilling to get vaccinated (n = 174, 8.2%) or undecided to take the COVID-19 vaccine (n = 730, 34.5%) were classified as vaccine hesitancy, which reported in 904 of 2196 in total (accounting for 41.2%).

The results of Binary logistic regression are shown in Table A2. Female (OR = 1.336, 95%CI: 1.001–1.783) and higher education (OR = 1.724, 95%CI: 1.114–2.666) was a risk factor for vaccine hesitancy. In the “3Cs” model, being in low-risk areas and no need to receive the vaccine (OR = 2.285, 95%CI: 1.501–3.789), being afraid of serious consequences caused by COVID-19 vaccination (OR = 1.929, 95%CI: 1.313–2.832), being in good health and no need to take the vaccine (OR = 1.891, 95%CI: 1.158–3.086), being concerned about short-term side effects of the vaccine (OR = 1.793, 95%CI: 1.074–2.994) and being concerned that the COVID-19 vaccine was ineffective (OR = 1.694, 95%CI: 1.160–2.474) were risk factor for vaccine hesitancy, indicating that medical students with these statements had more rejection or unsureness toward COVID-19 vaccination. Medical students believing the specialty of study or work environment made vaccination necessary (OR = 0.378, 95%CI: 0.252–0.568), thinking that they were susceptible to COVID-19 (OR = 0.411, 95%CI: 0.254–0.666) and when the vaccine was provided for free (OR = 0.519, 95%CI: 0.296–0.911) had more likeliness to receive the COVID-19 vaccine.

Discussion

Herd immunity through vaccination for controlling COVID-19 pandemic requires adequate vaccination coverage, but vaccine hesitancy made universal uptake of COVID-19 vaccines a challenge. 57.2% of medical students in our study were willing to get vaccinated against COVID-19, which is significantly lower than the previously study¹¹ that reported approximately 90% of the general population in China being willing to be vaccinated. The study by Wang et al.¹¹ was conducted in March 2020 (a year earlier) and they found that there no significant difference in age and region for vaccination acceptance. In this study, females reported slightly higher vaccine hesitancy (41.4%) compare with males. This may be that men were more likely to resort to pharmaceutical methods while women preferred to adopt non-pharmaceutical behaviors compare with males (e.g., hand washing, masking and sanitation).¹² Zintel et al¹³ had the same finding that men are more willing to have the COVID-19 vaccine. This may indicate that women are more likely to express concerns about the effectiveness and safety of the vaccine. One study¹⁴ reported 91.99% of medical students in Poland would like to take the COVID-19 vaccine. In our study, 41.2% of the medical students were hesitant about the COVID-19 vaccine. Another study,¹⁵ conducted among medical students in Egypt, found that 46% had vaccine hesitancy. Compared with these studies, the vaccine hesitancy in our sample population was not low, which would be a great challenge for the realization of herd immunity. Meanwhile, medical students are more likely to come into contact with patients during their usual clinical practice, internship, or standardized training, so they are more likely to be infected with COVID-19. Moreover, as future healthcare personnel, medical students, especially those already in internship or standardized training, are also responsible for providing vaccination advice for patients. They are also an important trusted source of vaccination information for patients. Considered as a reliable source of patients’ vaccine information, healthcare personnel attitudes toward vaccination can influence patients’ vaccination decisions.^16,17 Therefore, it is crucial to take effective evidence-based measures to reduce vaccine hesitancy among medical students.

We found that most factors for vaccine hesitancy among different population, as well as the medical students in our study, were associated with concerns about the safety and effectiveness of vaccines.¹⁸ In this study, lack of confidence in the COVID-19 vaccine (believing the vaccine was ineffective, fear of short-term side effects, and worrying about serious consequences of vaccination) was a risk factor for vaccine hesitancy, consistent with multiple studies.^19–22 The public may be vaccine hesitancy when there was insufficient information and data on the safety and effectiveness of the vaccine, and they would prefer to wait for reviewing more data to help them make vaccination decisions.^16,17 We found that individuals with higher education were more likely to report vaccine hesitancy. Previous studies indicated that individuals with higher education levels were more concerned about the risks and effects of vaccines, hence more precise scientific evidence may be needed to prove the safety and effectiveness of vaccines.^23,24 One study pointed out that although more than 90% of participants were willing to receive the COVID-19 vaccine, yet about 50% said they would postpone the vaccination until the safety of the vaccine was confirmed.¹¹ The effectiveness of a new vaccine is an important reflection of its effect and efficacy. Harapan et al.²⁵ pointed out that the public’s acceptance rate of the 95% effective COVID-19 vaccine was 93.3%, but acceptance rate of the 50% effective vaccine dropped to 67%. These may be explained that perception of benefits and risk could influence one’s behavior. The cognition of the benefits and risks of vaccines has a great influence on vaccination decision-making behavior. The public would weigh the risks and benefits of vaccination based on available vaccines information and data to make the most informed decision for themselves. Therefore, it’s essential to take tailored strategies to explain the possible benefits and risk in COVID-19 vaccination by scientific evidence and data, so as to strengthen trust in the vaccine.

Furthermore, studies showed that more confidence the public had in vaccines, more likely they were to get vaccinated.^14,26 Distrusting the COVID-19 vaccine may stem from having little confidence in the governments since vaccination is usually a government-led public health intervention. The rapid speed of development, authorization and implementation of COVID-19 vaccines has raised public concerns about the safety and efficacy of vaccines.^16,20,27,28 Previous studies found that the public threw suspicion on emergency authorization or accelerated approval of vaccines.^29,30 A poll in the United States suggested that the public believed the COVID-19 vaccine was politically driven rather than scientifically driven.³¹ A number of studies found that the public thought the development of COVID-19 vaccines was too political and distrusted the safety of COVID-19 vaccine, which ultimately led to vaccine hesitancy.^20,27,28,32 Hence, enhancing the credibility of governments in the vaccination campaigns is crucial to the public’s vaccine confidence which can contribute to improve vaccine acceptance. Supervising the development, approval and use of vaccines and ensuring the transparency of information may help government gain public trust. Social networks, TV broadcasting, etc. are important sources of vaccine information. These new media have the advantage of convenience and speed in disseminating information and data. However, misinformation and bad public opinion may also be quickly spread through these media, which would have negative effect on people’s vaccination willingness. Correcting misinformation and false perception in time to ensure correct orientation of public opinion is imperative.

More complacency (being in good health or in low-risk areas, there was no need to get vaccinated) was also an important risk factor for vaccine hesitancy. Medical students who thought they were healthy or in low-risk areas were more likely to report vaccine hesitancy, which may be explained that more complacency and lower perceived risk leads to vaccine hesitancy. Medical students who thought they were in good health may be more likely to believe in their immunity and may think they were less likely to be infected with COVID-19. Those in low-risk areas were less likely to be infected with COVID-19 which means the mild threat of COVID-19 on health. Previous studies found the same association. Kose et al.²¹ found that people who believed in their immunity were hesitant to get vaccinated. One study¹⁷ pointed out that 56.1% people refused to get vaccinated or were unsure whether to get vaccinated when the perceived impact of COVID-19 on their health was minimal or mild. Less complacency (believing they were susceptible to COVID-19), a protective factor for vaccine hesitancy, could promote COVID-19 vaccination, which is consistent with the findings of other studies.^8,19,33 Medical students with less complacency (believing their learning or working environment was special) were prone to receive COVID-19 vaccine. Perceived individual risk may influence attitudes and behavior change.³⁴ Kwok et al.⁵ pointed out that less complacency (self-perceived risk of disease) was associated with stronger intention to get vaccinated against COVID-19. One study¹⁹ indicated that positive changes occurred in health-care workers’ attitudes and behaviors toward influenza vaccination during the COVID-19 pandemic, which may be explained by the fact that the increase of perceived risk during the COVID-19 pandemic. Susceptibility and seriousness of COVID-19 should be focus on and emphasized to all people. No matter having in good health or being in low-risk areas, every person has the risk of infection during COVID-19 pandemic.

China is implementing free vaccination of the COVID-19 vaccines for all citizens. Our survey found that free vaccines policy increased the willingness of medical students to get vaccinated. Several studies found that the public were concerned about the fees when making vaccination decisions. Determann et al.³⁵ pointed out that the public were more willing to pay more for a more effective vaccine. Compared with free vaccination, higher out-of-pocket costs had a great impact on vaccination coverage. An early study in China found that public willingness to receive COVID-19 vaccine was higher when the vaccine was free available.³⁶ Another study³⁷ also pointed out that the public were concerned about the charges of vaccines generally and desired for free vaccination services. Therefore, the country should consider the people’s ability and willingness to pay when formulating vaccine charging standards. Countries with strong economic power may also consider implementing free vaccination, which could solve the availability of vaccine service firstly.

The study has some limitations. First, convenience sampling was adopted in the survey and the principle of randomization was not achieved. Second, the study was conducted in two medical schools, having limited sample representativeness, which may affect the universality and generalization of the findings. Thirdly, the survey was anonymous and online, so the response rate cannot be calculated. The self-report method may introduce reporting bias because the research objects participating in the survey may be more interested in the study. Fourth, the intention of taking the COVID-19 vaccine is affected by many factors. The intentions and attitudes of vaccination are not the actual vaccination behavior, which may change with time, environment, information and other factors.

Conclusions

More than 40% of medical students were hesitant to take the vaccine. We have confirmed that concerns about safety and efficacy of vaccines are barriers to get vaccinated. Individual perceived risk is a positive factor for vaccination. The accessibility of vaccine services (e.g., providing free vaccines) is an important catalyst for vaccination. Medical students, as future healthcare workers, are in the stage of education and learning, which is the key period for shaping health literacy. In future work, their health beliefs are bound to influence patients’ health attitudes. In the context of the COVID-19 pandemic, it is crucial to strengthen vaccines health literacy education for medical students, which has potential effects on improving vaccination coverage. Social platforms and news media are important sources of vaccination information, hence strengthening the management of information and news on vaccines is also critical to improve public confidence in vaccines.

Appendix A.

Table A1.

Demographic characteristics of the participants (N = 2196)

Variables	Options	Frequency (%)
Gender	Male	402 (18.3%)
	Female	1794 (81.7%)
Region	Urban	561 (25.5%)
	Rural	1635 (74.5%)
Education	Technical secondary school education and higher vocational school education	1516 (69%)
	Undergraduate and graduate education	680 (31%)
Grade	First grade	991 (45.1%)
	Second grade	916 (41.7%)
	Third grade	246 (11.2%)
	Fourth grade and above	43 (2%)
Specialty	Nursing	1414 (64.4%)
	Pharmaceutics	349 (15.9%)
	Rehabilitation Technology	152 (6.9%)
	Others	281 (12.8%)
Have you been vaccinated against COVID-19?	Yes	83 (3.8%)
	No	2113 (96.2%)
Would you like to take the COVID-19 vaccine if it is available now?	Yes	1209 (57.2%)
	No	174 (8.2%)
	Undecided	730 (34.5%)
Vaccine hesitancy	No	1292 (58.8%)
	Yes	904 (41.2%)
Access to COVID-19 vaccine information	WeChat, QQ, Weibo and other social networks	1812 (82.5%)
	Television broadcasting	1705 (77.6%)
	Health care personnel	1434 (65.3%)
	Classmates, friends, colleagues, families	1378 (62.8%)
	Publicity in public places	1142 (52%)
	Newspapers and periodicals	857 (39%)

Table A2.

Predictive factors related with COVID-19 vaccination in binary logistic analysis (N = 2196)

Variables	Not vaccine hesitancy, No. (%)	Vaccine hesitancy, No. (%)	OR (95%CI)	P
Age (years), mean ± SD	17.64 ± 2.25	17.69 ± 2.253	0.999 (0.907–1.100)	0.986
Gender
Male	240 (59.7%)	162 (40.3%)	Ref
Female	1052 (58.6%)	742 (41.4%)	1.336 (1.001–1.783)	0.049
Region
Urban	337 (60.1%)	224 (39.9%)	Ref
Rural	955 (58.4%)	680 (41.6%)	1.069 (0.849–1.346)	0.571
Education
Technical secondary school education and higher vocational school education	910 (60%)	606 (40%)	Ref
Undergraduate and graduate education	382 (56.2%)	298 (43.8%)	1.724 (1.114–2.666)	0.014
Grade
First grade	547 (55.2%)	444 (44.8%)	Ref
Second grade	570 (62.2%)	346 (37.8%)	0.778 (0.614–0.983)	0.037
Third grade	150 (61%)	96 (39%)	0.632 (0.406–0.905)	0.042
Fourth grade and above	25 (58.1%)	18 (41.9%)	0.666 (0.309–1.433)	0.298
Specialty
Nursing	845 (59.8%)	569 (40.2%)	Ref
Pharmaceutics	195 (55.9%)	154 (44.1%)	1.486 (1.110–1.990)	0.008
Rehabilitation Technology	85 (55.9%)	67 (44.1%)	1.419 (0.933–2.157)	0.102
Others	167 (59.4%)	114 (40.6%)	0.904 (0.648–1.261)	0.552
I am concerned that the COVID-19 vaccine is ineffective
Disagree	441 (74.4%)	152 (25.6%)	Ref
Unsure	704 (53.9%)	601 (46.1%)	1.349 (1.015–1.793)	0.039
Agree	147 (49.3%)	151 (50.7%)	1.694 (1.160–2.474)	0.006
I am concerned about the short-term side effects of the COVID-19 vaccine
Disagree	128 (76.6%)	39 (23.4%)	Ref
Unsure	777 (59.2%)	535 (40.8%)	1.166 (0.707–1.922)	0.547
Agree	387 (54%)	330 (46%)	1.793 (1.074–2.994)	0.026
I think I’m susceptible to COVID-19
Disagree	652 (60.3%)	429 (39.7%)	Ref
Unsure	516 (54.6%)	429 (45.4%)	0.996 (0.739–1.262)	0.799
Agree	124 (72.9%)	46 (27.1%)	0.411 (0.254–0.666)	0.000
It is necessary for me to be vaccinated against COVID due to the specialty of study or work environment
Disagree	73 (41.2%)	104 (58.8%)	Ref
Unsure	478 (46.2%)	557 (53.8%)	0.778 (0.517–1.171)	0.229
Agree	741 (75.3%)	243 (24.7%)	0.378 (0.252–0.568)	0.000
I think I am in good health and there is no need to take the COVID-19 vaccine
Disagree	865 (73%)	320 (27%)	Ref
Unsure	361 (42.9%)	480 (57.1%)	1.816 (1.354–2.436)	0.000
Agree	66 (38.8%)	104 (61.2%)	1.891 (1.158–3.086)	0.011
Being in a low-risk area, I don’t think I need to be vaccinated against COVID-19
Disagree	833 (73.8%)	296 (26.2%)	Ref
Unsure	385 (44.7%)	477 (55.3%)	1.405 (1.049–1.883)	0.023
Agree	74 (36.1%)	131 (63.9%)	2.285 (1.501–3.789)	0.000
I am afraid of the serious consequences of COVID-19 vaccination
Disagree	486 (78.1%)	136(21.9%)	Ref
Unsure	655 (52.1%)	602(47.9%)	1.363 (1.003–1.853)	0.048
Agree	151 (47.6%)	166(52.4%)	1.929 (1.313–2.832)	0.001
I am willing to get vaccinated because of the free policy of COVID-19 vaccines
Disagree	50 (54.9%)	41 (45.1%)	Ref
Unsure	365 (40.7%)	531 (59.3%)	1.063 (0.593–1.904)	0.837
Agree	877 (72.5%)	332 (27.5%)	0.519 (0.296–0.911)	0.022

Ref: reference.

Funding Statement

This research received no external funding.

Author contributions

Mei Li and Yanhua Chen conceived the study. Yu Zheng and Mei Li designed the questionnaire. Mei Li, Yu Zheng, Yue Luo, Dinglin Fan and Xingli Yu collected data. Mei Li, Jian Tang and Jianlan Ren analyzed data. Mei Li, Yue Luo, Linrui Jiang and Dongmei Luo interpreted the findings. Mei Li wrote the paper. Yanhua Chen was responsible for the entire supervision. All authors have read and agreed to the published version of the manuscript.

Data availability

All data is included in the manuscript.

Disclosure of potential conflicts of interest

No potential conflicts of interest were disclosed.

Ethical approval

This study was approved by the Ethics Committee of the Affiliated Hospital of Southwest Medical University, Luzhou. Furthermore, the questionnaires were anonymous.

Informed consent

Based on the principle of informed consent, this study was anonymous and voluntary.