key: cord-0981962-q9j91u0t
authors: Duong, Minh Cuong; Duong, Bich Thuy; Nguyen, Hong Trang; Quynh, Trang Nguyen Thi; Nguyen, Duy Phong
title: Knowledge about COVID-19 vaccine and vaccination in Vietnam: a population survey
date: 2022-01-19
journal: J Am Pharm Assoc (2003)
DOI: 10.1016/j.japh.2022.01.014
sha: 7a94840e22bd85a8a93bd2fb705e2e56553e21c4
doc_id: 981962
cord_uid: q9j91u0t

Background COVID-19 vaccine acceptance is essential in controlling the virus. Vaccine knowledge influences vaccine acceptance and understanding this is vital in planning immunization strategies. Objectives This study aimed to examine the public COVID-19 vaccine knowledge levels and predictors of low knowledge levels in Vietnam. Methods A cross-sectional, community-based survey was conducted between 16 April and 16 July 2021. To examine the community knowledge levels regarding the vaccine essentialness and efficacy, a self-administered questionnaire was developed and was comprised of seven questions with five Likert scale responses corresponding to the levels of agreement/disagreement with the provided statements and scores ranging from 0-4. An individual’s knowledge score above the mean score of all participants was defined as ‘acceptable’ and that below was defined as ‘low’. Results Among 1708 respondents, the mean age was 34.3 ± 13.4 years, 942 (55.2%) were females, and 797 (46.7%) had acceptable knowledge levels. Age (adjusted odds ratio [AOR]=0.984, 95% confidence interval [CI]: 0.972-0.995, P=0.005) and being vaccinated against COVID-19 (AOR=0.653, 95%CI: 0.431–0.991, P=0.045) were inversely associated with lower knowledge levels. Those with a Gapminder income of $8-<$15 per day (AOR=1.613, 95%CI: 1.117–2.329, P=0.001), $2-<$8 (AOR=2.093, 95%CI: 1.313–3.335, P=0.002), and <$2 (AOR=3.341, 95%CI: 1.951–5.722, P<0.001), less than a high school education (AOR=4.214, 95%CI: 1.616–10.988, P=0.003), and non-clinical professionals and/or non-health lecturers (AOR=1.83, 95%CI: 1.146–2.922, P=0.01) were positively associated with lower knowledge levels. Conclusion To ensure a successful vaccine rollout, it is crucial to improve community knowledge about vaccine essentialness and efficacy. Those who are at young age, have low income and/or education levels, and working in non-clinical and non-health education fields should be the target of the intervention programs. Community education programs may benefit from using those who have been immunized as role models.

The Coronavirus Disease 2019 (COVID-19) pandemic has caused enormous economic hardship, morbidity, and mortality. 1 Preventative measures including quarantine and social distancing, regular hand hygiene, and use of face masks in public have been implemented worldwide. [2] [3] [4] [5] These efforts alone, however, have proven insufficient to completely control viral transmission and hospitalizations due to Vaccination remains one of the most effective measures in the fight against infectious diseases. 1 In the context of COVID-19, in addition to other control measures, vaccination plays an important role in paving the way to eliminate COVID-19. 6 Hence, development of a safe and effective COVID-19 immunization is the long-term solution towards averting the pandemic for most countries. 7 However, the availability of a vaccine does not guarantee sufficient population vaccination coverage. 8 Like other vaccine preventable diseases, uptake of COVID-19 vaccine is multifactorial and includes the knowledge about the vaccine. [9] [10] [11] Giving people information or education to assist them in making informed decisions about their health is an important part of all patient-centered health systems. 10 Given that COVID-19 vaccines are being used, identifying those in most need of this information is crucial to improving vaccine uptake and ensuring equity within health systems. 12 10 General knowledge about COVID-19 vaccines is highly variable with surveys reporting 'correct answers' between 26% and 86% in Ethiopia, Jordan, Oman, Bangladesh, India, Libya, and Italy. 9,12-17 COVID-19 vaccine knowledge is associated with age, income and education levels, medical-related professions, and COVID-19 immunization status; however, these may also be context-dependent. 14, 16, 17 The objective of this study was to examine the general community's COVID-19 vaccine knowledge and associated predictors in Vietnam. This study was significant because it will assist Vietnam and comparable countries in guiding interventional measures aimed at building and maintaining community's receptiveness of COVID-19 vaccine,

Vietnam has experienced the fourth COVID-19 wave starting on 27 April 2021. 23 This is considered the first "real wave" with 40,609 cumulative incident cases being reported in more than half (52.4%, 33/63) of cities across Vietnam as of the end of the study period. 23 Of these affected areas, Ho Chi Minh Cityone of the two research sites for the paper-based survey was hit hard by the outbreak with 23,913 (58.9%) cumulative incident cases. 23, 24 Considering this situation, we were able to examine the public COVID-19 vaccine knowledge in the context of an ongoing severe COVID-19 outbreak. During this time, the AstraZeneca/Oxford COVID-19 vaccine was available to priority groups including frontline healthcare workers and those working in COVID-19 prevention and control. A few fatal cases related to COVID-19 vaccine were reported. 25, 26 Vietnam has started its largest-ever COVID-19 vaccination campaign since 10 July 2021. 27

A cross-sectional, anonymous survey using a self-administered questionnaire was conducted across Vietnam between 16 April 2021 and 16 July 2021. The questionnaire was administered by two different data collection methods including online and paper-based questionnaires. The paid SurveyMonkey platform (www.surveymonkey.com) was used for the online component of the survey given favorable characteristics of SurveyMonkey including easier access, avoidance of input and data coding errors, and faster distribution. the study. Vietnamese people aged 18 and older who were able to read and answer the survey were eligible to participate in the study. After the survey, information on the year of birth of participants was used to cross-check their age. Data of those participants aged younger than 18 were excluded from the analysis. At the end of the data collection period, to prevent duplicate entries obtained from the online survey, entries submitted from the same IP address were separately reviewed by the researchers (MCD and HTN) and included in the analysis once consensus was reached. The study was approved by the Phenikaa University Ethics Committee (reference 216/QĐ-ĐHP-KHCN).

To recruit both online and paper-based participants, a snowball sampling technique was used, utilizing the authors' current social networks including family members, friends and colleagues in Vietnam who were healthcare professionals, university lecturers, students, and people in the general community.

Essentially, this method is a chain-referral sampling where existing participants recruit future participants from among their acquaintances. 30 A recruitment poster together with the survey link was emailed to the authors' social networks and posted to their accounts on LinkedIn, Zalo, and Facebook which are the most common social media apps in Vietnam. A request to disseminate the poster and the survey link to the recipients' social networks was also included in the poster so that online responses could be from across Vietnam. The paper-based survey was conducted in Ho Chi Minh City, which is the largest city and located in southern Vietnam, and Hanoi, which is the capital and located in northern Vietnam. The rationale for selecting these cities as research sites was that these cities are the two largest cities and the main destinations of internal migration in Vietnam. 31 Therefore, selecting these research sites would enable us to have study participants from different socioeconomic backgrounds and regions in Vietnam. Paper-based participants may opt to complete the online survey, if they had an internet enabled device and/or internet connection.

A self-administered questionnaire was designed specifically to be completed by respondents without intervention of the researchers and was comprised of two parts: demographics and Covid-19 vaccine Therefore, the total maximum knowledge score was 28. These seven questions were developed based on the available literature about COVID-19 vaccines and information from the manufacturers, World Health Organization (WHO), and Vietnam Ministry of Health. 24,27,34-40 Pilot online and paper-based surveys were conducted and included 100 individuals (i.e., 50 participants each) from different backgrounds to help refine the final survey and confirm its validity and reliability. 41 To ensure study participants' understanding of the questionnaire, the online and paper-based surveys used a questionnaire that was written in Vietnamese.

Contact details of the researchers (MCD and HTN) were provided so that study participants could contact for assistance.

Data were analyzed using the Statistical Package for the Social Sciences (SPSS) version 26 (IBM).

Continuous variables were displayed as mean ± one standard deviation (SD), and range. Categorical variables were presented as a count and percentage. Study participants' vaccine knowledge levels were defined in relation to the mean score achieved by all participants. Scores above the mean were defined as 'acceptable' and those below were defined as 'low.' This analysis approach has been validated elsewhere. 18 Chi-squared test and Chi-squared test for trend were used to compare categorical data. Student's t-test was utilized to compare continuous data. A binary logistic regression model was developed to examine predictors of a low vaccine knowledge. All independent variables were entered into the model. Alpha was set at 5% level.

The online survey was a part of this study. Like the online survey, the paper-based survey utilized the snowball sampling technique to recruit participants. Therefore, to increase the study's transparency and possibilities for interpreting the results, this paper was reported in accordance with the recommended Checklist for Reporting 

A total of 1872 people including 1003 (53.6%) paper-based and 869 (46.4%) online participants agreed to participate in the study (Figure 1 ). Of these 1872 people, 164 online participants (8.8%) had missing J o u r n a l P r e -p r o o f answers and were removed from the analysis. Therefore, 1708 (91.2%) people were included in the study.

The mean age of all participants was 34.3  13.4 years ( Table 1) . Female participants accounted for 55.2%

(942/1708). Just under half (49.6%, 847/1708) of participants was from southern Vietnam, more than twothird (69.3%, 1184/1708) earned less than $15 per day, and 74.5% (1272/1708) lived with their family. Most (81.9%, 1399/1708) participants had an undergraduate and/or a postgraduate degree, and 72.2% (1234/1708) were students of non-health related subjects or people working in non-health related fields. Only 222 (13%) participants had chronic health conditions, 48 (2.8%) had experiences with COVID-19 disease, and 129 (7.6%) were vaccinated.

Given that the maximum number of points awarded for correct answers of each of seven knowledge questions was four, the percentage of participants who got four points for each question ranged from 2.2% to 41.6% (Appendix 2). Only 2.2% (38/1708) strongly disagreed that they are completely protected against COVID-19 and 36.4% (621/1708) strongly disagreed that they do not need to undertake any other preventive measures after they fully complete the vaccination schedule. Less than one-third strongly agreed that being vaccinated themselves contributes to the protection of the community against COVID-19 (30.3%, 518/1708) and getting vaccinated is a good way to protect oneself from COVID-19 (20.6%, 352/1708). Less than half (41.6%, 710/1708) strongly disagreed that they do not need to get vaccinated because the outbreak was controlled very well in Vietnam. Less than one-fifth strongly agreed that vaccines developed by different manufacturers have different levels of efficacy (17.1%, 292/1708), and the available vaccines may not be effective on new variants compared with the original strain detected in Wuhan (12.8%, 219/1708).

The mean knowledge score of all participants was 19.2 ± 2.8 (Table 2) Predictors of a low level of vaccine knowledge J o u r n a l P r e -p r o o f A low knowledge level was significantly associated with age, gender, region, Gap minder income levels and jobs (P<0.001), and education levels (P=0.035) ( higher odds of having a low knowledge level compared with those whose Gapminder income was $32 or more per day. Having an education level of less than high school was positively associated with a low knowledge level compared with those whose education levels was undergraduate or above (AOR=4.214, 

Although there are similar studies conducted in other countries, 9, [12] [13] [14] [15] there was no study in Vietnam.

To the best of our knowledge, this is the first study examining the level of COVID-19 vaccine knowledge in the general community in Vietnam. Our study identifies priority groups for intervention. The study also allowed us to get insight into the vaccine knowledge levels of different health professional groups who are central to vaccination education and role models, particularly those who are not clinical doctors such as nurses and pharmacists.

The study included 1708 selected individuals across Vietnam, including large cities and those with a high COVID-19 burden. The distribution of our participants by region of residence was skewed to southern Vietnam (49.6%) provided that this region accounts for 36% of the total population in Vietnam. 45 This may also explain the low number of participants experiencing COVID disease in our study given that the fourth COVID-19 wave started in northern Vietnam. The number of participants getting vaccinated was low J o u r n a l P r e -p r o o f because the vaccine was exclusively available to frontline healthcare workers during the study period.

Participants aged between 21 and 60 years and female gender were predominant in our study which were comparable with the age and gender distributions in Vietnam. 45 Given that the average income per day in Vietnam is $9.8, 46 more than two-third (69.3%) of our participants earned less than $15 per day.

We found that more than half (53.3%) of participants had low vaccine knowledge levels. Given the mean knowledge score of 19.2 achieved by all participants, high proportions of participants having low knowledge levels, defined as their knowledge scores lower than this mean score, were documented in large cities across Vietnam. Our overall rate of low vaccine knowledge was comparable to that reported in community surveys conducted in India and Jordan. 15,16 However, our proportion was higher than that reported in Bangladesh (43%, 713/1658) and Ethiopia (26%, 128/492). 9, 14 Although the questionnaires used in these studies were not the same, all questionnaires aim to explore essential aspects of COVID-19 vaccine knowledge including the vaccine availability, essentialness, eligibility, efficacy, and side effects, all of which plays a role in facilitating the community's vaccine confidence and acceptance. 9, 47 In Vietnam, our finding regarding the proportion of people having low vaccine knowledge levels was inconsistent with studies examining the levels of knowledge towards COVID-19 disease and associated non-vaccine prevention and control measures. In detail, acceptable knowledge levels towards COVID-19 disease and associated non-vaccine prevention and control measures were documented in both the general community and specific groups including pharmacists and university students. 5,48-51

We found that young age as well as low income and education levels were associated with low vaccine knowledge levels. Our findings were consistent with previous studies in other countries. 14,16 It has been documented that young age, low income and educations levels are significantly related to low levels of health knowledge in general probably because these groups are less likely to have heard of the health information. 52 In contrast, people with high education levels are more knowledgeable and concerned about their health and life events that could impact them, such as COVID-19 vaccinations, through access to more sources of health information. 14 In line with another study, we found that being vaccinated against COVID-19 was associated with a good vaccine knowledge level. 17 It is documented that healthcare workers who are willing to be COVID-19 vaccinated serve as an important role model function for the public. 53,54 It has also been found that the public vaccine acceptance is influenced by their peers and social networks. 55 

Considering our finding of a positive association between being vaccinated against COVID-19 and acceptable vaccine knowledge levels, we believe that regardless of the professions, people who are vaccinated can present role models for the community. Future research is needed to examine how the community education programs using these role models could effectively approach different population groups.

In our study, participants working in health-related fields rather than clinical doctors and/or health lecturers such as nurses and pharmacists were more likely to have lower knowledge levels compared with clinical doctors and health lecturers. To the best of our knowledge, there is no study examining the levels of COVID-19 vaccine knowledge among different health professional groups in Vietnam. However, a study conducted on Vietnamese health students found a difference in the levels of COVID-19 vaccine acceptance by their specialist fields with more public health students but less preventive medicine students accepting the vaccine compared with general medicine students although the differences in levels of vaccine knowledge between these students were not examined. 56 Similarly, a study in the United States found that direct medical care providers had higher vaccine acceptance (49%, 595/1207) than other health professionals although the vaccine knowledge levels among health professionals were not examined. 57 It should be noted that this US study was conducted between 7 October and 9 November 2020 and thus, vaccine acceptance rate of this study population may have increased due to the recent changes in the local COVID-19 situations and community education regarding COVID-19 vaccination. Studies in Jordan and Italy found that healthcare workers had higher vaccine knowledge levels compared with nonmedical-related professions. 16, 17 The finding of our study was different than the Jordanian and Italian studies probably because of the difference in selecting the reference group. Based on our experience with the Vietnam context, clinical doctors and health lecturers are updated with medical scientific publications more regularly than those working in other health and non-health related fields and thus, were selected as our reference group. By doing this, we could be able to compare the vaccine knowledge levels of other health professionals who were not physicians and health lecturers with those of physicians and health lecturers. Unlike us, none of the Jordanian and Italian studies examined the differences in the vaccine knowledge levels between different health professional groups. Our study makes it possible to highlight the differences in the vaccine knowledge levels between health professional groups and therefore, helps in developing more targeted J o u r n a l P r e -p r o o f intervention programs. It is clear that in addition to vaccine knowledge, COVID-19 vaccine acceptance was influenced by other factors including enabling environments (e.g. convenient vaccination places and easy and accessible vaccination booking), social influences (e.g. salient social norms in favor of vaccination), and motivation (e.g. increasing motivation to get vaccinated through building timely trust in vaccines). 36 However, like our study, the varied vaccine acceptance rates in different occupational roles in healthcare found in the US study implied that the non-clinical professionals should be targeted -with educational interventions to ensure a successful COVID-19 vaccination. It should be noted that health professionals such as pharmacists, rather than physicians, have been identified as a professional figure in the health section who is qualified to improve the public vaccine acceptance in general. 58 Indeed, a study in Vietnam also found that community pharmacists could take an important part in disseminating COVID-19 related knowledge to the public. 50 Hence, to ensure a successful COVID-19 vaccine rollout, education programs in Vietnam should focus on improving the vaccine knowledge in those who are working in health-related fields but are not clinical doctors and/or health lecturers, such as nurses and pharmacists. Further studies are needed to examine the reasons for the low levels of vaccine knowledge in this group.

We found that only 41.6% of participants believed that vaccination was needed, despite the ongoing COVID-19 outbreak in Vietnam. In addition, only 20.6% of participants strongly agreed that getting vaccinated was a good way to protect oneself from COVID-19. At the time this manuscript was developed, the local government had been implemented the largest-ever vaccination campaign together with other preventive measures to control the outbreak. 27 This implies that vaccination together with these measures may be the only way to achieve this goal as can be seen in other vaccine preventable diseases. 6, 59 In light of this, community education needs to emphasize the importance of the combined vaccination and non-vaccine measures in controlling the outbreak.

Our participants' vaccine knowledge regarding vaccine efficacy and essentialness needs to be improved because 16.2% of participants strongly agreed that they were completely protected against COVID-19 after they fully completed the vaccination schedule. Only 36.4% of participants strongly disagreed that they did not need to undertake any other preventive measures after they fully completed the vaccination schedule. In addition, less than one-fifth of participants strongly agreed that vaccines developed by different manufacturers had different levels of efficacy (17.1%), and the available vaccines may not be J o u r n a l P r e -p r o o f effective on new variants compared with the original strain (12.8%). The WHO has emphasized the importance of managing the community's expectations towards the vaccine to ensure that those who have been vaccinated do not stop practicing protective behaviors. 36 Another issue is that only 30.3% of our participants strongly agreed that being vaccinated themselves contributed to the protection of the community against COVID-19. Vaccination not only protects oneself from COVID-19, but also helps create herd immunity to stop its spread and protect vulnerable groups who cannot get vaccinated. 37 It is estimated that 65-70% of the population needs to be vaccinated to achieve herd immunity against COVID-19. 37 Hence, vaccination can be conceptualized as a social responsibility which plays an important role in educating the community regarding the essentialness of COVID-19 vaccination. 60 Indeed, it is documented that social responsibility is positively associated with COVID-19 vaccination intention. 61 Considering the loss of life and economic consequences due to COVID-19, social responsibility attached to vaccination should be emphasized by governments. 60 Our findings highlight the need to tailor the current education program to enhance the community knowledge regarding both the essentialness and efficacy of vaccine.

Our study has some limitations. Firstly, the government started the largest-ever COVID-19 vaccination program and enhanced the community education towards COVID-19 vaccines on the media to respond to an outbreak of COVID-19 during the study period. This may have influenced our participants' responses to the survey. However, we believe that it is negligible since we ended the study when the program started. Nevertheless, we have identified room for improvement of the community education programs. Secondly, many cities in Vietnam had been under lockdown during the study period making the online survey the most efficient method to collect data at large. Given the online survey, duplicate entries may be an issue and affect the validity of the study. However, before completing the survey, participants were asked to read the participant information sheet outlining the research purposes and what participants were required to do. Only participants who fully understood and agreed to participate in the study were enrolled in the study. We screened and reviewed potentially duplicate entries, and although we could not remove duplicates completely, these strategies should make them negligible. Thirdly, given our study aimed to target the community at large, recruiting participants using a snowball sampling technique could cause selection bias. However, in addition to the online survey, we utilized a paper-based recruitment procedure in two largest cities in Vietnam to include those who were unable to complete the online survey such as the J o u r n a l P r e -p r o o f elderly and those who did not have an internet enabled device and/or internet connection. The use of a combination of two different, complementary data collection methods helped include a diverse study population in our study, which increased the generalizability of the study's results. Lastly, responses to our vaccine knowledge questions can be influenced by study participants' anti-vaccination attitudes which were not assessed in this study. Consequently, our study may underestimate the true vaccine knowledge level among participants who want to avoid all vaccination or COVID-19 vaccination (anti-vaxxers).

People who are at young age, have low income and/or education levels, and work in non-clinical and non-health education fields have low COVID-19 vaccine knowledge levels. To ensure a successful COVID-19 vaccine rollout and sustainable control and prevention of COVID-19, it is crucial to improve the knowledge about vaccine essentialness and efficacy in the community. Community education programs may be beneficial from using those who have been vaccinated as role models. J o u r n a l P r e -p r o o f J o u r n a l P r e -p r o o f 

On the road to ending the COVID-19 pandemic: Are we there yet?

Narrative review of non-pharmaceutical behavioural measures for the prevention of COVID-19 (SARS-CoV-2) based on the Health-EDRM framework

Herd Immunity to COVID-19

COVID-19 vaccine hesitancy and resistance: Correlates in a nationally representative longitudinal survey of the Australian population

Vaccine hesitancy: the next challenge in the fight against COVID-19. European journal of epidemiology

Understanding of COVID-19 Vaccine Knowledge, Attitude, Acceptance, and Determinates of COVID-19 Vaccine Acceptance Among Adult Population in Ethiopia

Interventions aimed at communities to inform and/or educate about early childhood vaccination. The Cochrane database of systematic reviews

COVID-19 vaccine hesitancy in the UK: the Oxford coronavirus explanations, attitudes, and narratives survey (Oceans) II

Attitudes, and Practices (KAP) toward the COVID-19 Vaccine in Oman: A Pre-Campaign Cross-Sectional Study. Vaccines (Basel)

Knowledge, attitude, and acceptance of healthcare workers and the public regarding the COVID-19 vaccine: a cross-sectional study

Factors affecting the public's knowledge about COVID-19 vaccines and the influence of knowledge on their decision to get vaccinated

Knowledge and Acceptance of COVID-19 Vaccination among Undergraduate Students from Central and Southern Italy. Vaccines (Basel)

The Levels of COVID-19 Related Health Literacy among University Students in Vietnam

Well-Being of Healthcare Workers and the General Public during the COVID-19 Pandemic in Vietnam: An Online Survey. International journal of environmental research and public health

Rural-urban differences in preferences for influenza vaccination among women of childbearing age: implications for local vaccination service implementation in Vietnam

Information on the case of death after receving vaccine against COVID-19

Ministry of Health

Ministry of Health. Hanoi offficially provided information on a young, male teacher who died after receiving COVID-19 vaccine

Advantages and Disadvantages of using the website SurveyMonkey in a real study: Psychopathological profile in people with normal-weight, overweight and obesity in a community sample

Knowledge, attitudes, and practices towards COVID-19 among

Chinese residents during the rapid rise period of the COVID-19 outbreak: a quick online cross-sectional survey

Pros and cons of different sampling techniques

COVID-19 Vaccine AstraZeneca confirms 100% protection against severe disease, hospitalisation and death in the primary analysis of Phase III trials

vaccine-astrazeneca-confirms-protection-against-severe-disease-hospitalisation-and-death-in-the-primaryanalysis-of-phase-iii-trials

World Health Organization. Behavioural cosiderations for acceptance and uptake of COVID-19 vaccines

COVID-19 herd immunity: where are we?

Safety and Efficacy of the BNT162b2 mRNA Covid-19

Effectiveness of Covid-19 Vaccines against the 44

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: guidelines for reporting observational studies

General Statistics Office. Completed results of the 2019 Vietnam population and housing census

The Levels of COVID-19 Related Health Literacy among University Students in Vietnam

Knowledge, Attitudes, and Practices of the Vietnamese as Key Factors in Controlling COVID-19

Knowledge, attitude and practices of community pharmacists 54

Hesitancy of Arab Healthcare Workers towards COVID-19

Vaccination: A Large-Scale Multinational Study. Vaccines (Basel)

Negotiating vaccine acceptance in an era of reluctance

Predictors of Intention to Get a COVID

Vaccine of Health Science Students: A Cross-Sectional Study. Risk management and healthcare policy

COVID-19 Vaccine Acceptance among Health Care Workers in the United States. Vaccines (Basel)

The pharmacist's role in health information, vaccination and health promotion

Simply put: Vaccination saves lives

Hopes, hesitancy and the risky business of vaccine development

Prosociality and Social Responsibility Were Associated With Intention of COVID-19 Vaccination Among University Students in China. International journal of health policy and management

Acquiring COVID-19 and/or having family member(s) or friend(s)/colleague(s) acquiring COVID-19 COVID-19