The Coronavirus disease 2019 (COVID-19) is a global pandemic that is affecting 210 countries and territories around the world. By the end of March 2020, the total number of infected cases have been exceeded 3,000,000 and more than 200,000 deaths. 1 Vietnam is a low-resource country that have a good response to the outbreak with only 260 cases and no deaths, thanks to the highly restricted infection prevention and control policy. 2 On 28 March 2020, the government of Hanoi locked down one of largest medical centers in the country (Bach Mai Hospital) after a large outbreak have been detected in staff and linked patients. 3 At the Center for Tropical Diseases where the first 2 cases were identified, all healthcare workers (HCWs) have been quarantined for more than 3 weeks. 4 The psychological distress of quarantine has been well-documented, includes stress, anxiety, confusion, fear, insomnia and post-quarantine related stigmatization; and the impact on HCWs might be greater than general population in most of aspects. 5 We aims to measure the stigma experienced and its association with mental health problems among HCWs after 23 days of quarantined at Bach Mai Hospital (BMH).
We collected data from healthcare workers between 26-29 April 2020. We developed a selfreported instrument that measure COVID-19 related stigma among participants. The questionnaires consist of 12 questions with answer option is a 4-point Likert scale. Responses were summed to calculate a total score; and higher scores indicate a higher level of stigma (Table   1) . We referred to the Berger-HIV Stigma Scale for the use of the terms and phrases of measurement items. 6 The validity assessment followed the COSMIN Risk of Bias checklist (Appendix S2). 7 . The study was approved by the Director board of BMH, and all participants provided informed consents. The details of methods was reported in Appendix S1.
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Of total of 61 participants enrolled to the study, female was 82.0% and median age was 32 years old (IQR=29-36). Most of the samples were nurses (73.8%) ( Table S1 ). The prevalence of depression, anxiety and stress were 13.11%, 14.75% and 4.92%, respectively ( Figure S1 ).
The total score of stigma scale was 11 (IQR=6-15; Min-Max=0-24). Three dimensions reconstructed from factor analysis, includes "negative self-image ", "disclosure concerns and personalized stigma", and "concerns about public attitudes". Each domains score was calculated by dividing the total score by the number of items (possible range of 0 -3). Cronbach's alpha was good to great in all domain factors, ranged from 0.75 to 0.86. Stigma domains showed a moderate correlation with DAS-21 subscales score.
One of the determinants of the success of outbreak contamination in Vietnam is that the government have been applied an early and constantly aggressive approach, includes zoning, isolating and quarantining all infected people and their close contacts; 2 as well as, improving the awareness of all citizens by mass media campaign by both traditional and modern means. 8 This may inadvertently increases the likelihood of being stigmatized in people after quarantined regardless their infection status. In front-line HCWs, the negative impacts could be more serious when they are the group with greater attention in the press and public media. In our results, higher level stigma was found in "negative self-image" and "concerns about public attitudes" domains, with the most common were the feeling of guilt towards family members and friends, and the avoidance of contact from the neighborhoods and the community. This finding needs to be further studied as the social distancing policy still in effect, and the results are only showed the short-term effects. Other limitations include the small sample size, using an instrument that has not been extensively validated to measure the stigma, and the insufficient of baseline data. In addition, the sample from BMH did not represent all HCWs in Vietnam, and cross-sectional design might not be able to establish causal inference.
To our knowledge, this the first study to report the COVID-19 related stigma among HCWs who experienced a long duration of quarantine in the country. Vietnam has succeeded in preventing This article is protected by copyright. All rights reserved.
the outbreak from widespread during the first two phases of the outbreak with the epicenter in China and European Union. The third phase will start soon after the government plan to receive thousands of citizens returning from abroad. 9 As the primary workforce, minimize the pressure and burden from non-work sources should be prioritized, as well as implement formal psychological supports if necessary. In addition, further studies to investigate society impact of COVID-19 and related policies should be conducted soon to prepare for the next stage of the outbreak. 