Sero-Prevalence of SARS-CoV-2 Antibodies in High-Risk Populations in Vietnam

• Main Authors: Tasnim Hasan, Thach Ngoc Pham, Thu Anh Nguyen, Hien Thi Thu Le, Duyet Van Le, Thuy Thi Dang, Trang Dinh Van, Yen Ngoc Pham, Ha Viet Nguyen, Giang Linh Tran, Van Thi Cam Nguyen, Thanh Trung Nguyen, Viet Quang Truong, Than Huu Dao, Chung Thanh Le, Nam Tan Truong, Hoang Trung Vo, Phuc Thanh Le, Thao Thanh Nguyen, Vinh Van Luu, Vinh Dai Nguyen, Brett G. Toelle, Guy B. Marks, Greg J. Fox
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: International Journal of Environmental Research and Public Health
• Subjects: COVID-19; SARS-CoV-2; seroprevalence; Vietnam
• Online Access: https://www.mdpi.com/1660-4601/18/12/6353
• ISSN: 1661-7827; 1660-4601

As a response to the coronavirus disease 2019 (COVID-19) pandemic, Vietnam enforced strict quarantine, contact tracing and physical distancing policies resulting in one of the lowest numbers of individuals infected with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) globally. This study aimed to determine the prevalence of SARS-CoV-2 antibody positivity among high-risk populations in Vietnam. A prevalence survey was undertaken within four communities in Vietnam, where at least two COVID-19 cases had been confirmed. Participants were classified according to the location of exposure: household contacts, close contacts, community members, and healthcare workers (HCWs) responsible for treating COVID-19 cases. Participants completed a baseline questionnaire and SARS-CoV-2 IgG antibodies were quantified using a commercial assay. A total of 3049 community members and 149 health care workers consented to the study. Among 13 individuals who were seropositive (0.4%), five household contacts (5/27, 18.5%), one close contact (1/53, 1.9%), and seven community members (7/2954, 0.2%) had detectable SARS-CoV-2 antibodies. All HCWs were negative for SARS-CoV-2 antibodies. Participants were tested a median of 15.1 (interquartile range from 14.9 to 15.2) weeks after exposure. Our study found a low prevalence of SARS-CoV-2 antibodies in high-risk communities and healthcare workers in communities in Vietnam with known COVID-19 cases.