Takalay S. auteur aut IRD Ngo-Giang-Huong Nicole auteur aut IRD Kongnim W. auteur aut IRD Mongkolwat P. auteur aut IRD Phoseng P. auteur aut IRD Wangsaeng N. auteur aut IRD Hongjaisee S. auteur aut IRD Butr-Indr B. auteur aut IRD Tragoolpua K. auteur aut IRD Jourdain Gonzague auteur aut IRD Pornprasert S. auteur aut IRD Khamduang W. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Non-healthcare workers with a high potential for exposure to severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) may contribute to the virus spreading. Data among asymptomatic and high exposure risk populations is still scarce, in particular Chiang Mai and Lamphun provinces, Thailand. We conducted a cross-sectional observational study aiming to assess the prevalence of SARS-CoV-2 RNA positivity, anti-SARS-CoV-2 IgM/IgG, and potential associated factors among asymptomatic/mild symptomatic individuals with a high exposure risk in Chiang Mai and Lamphun provinces, during the second wave of outbreak in Thailand (November 2020-January 2021). Socio-demographic data was collected through an on-line questionnaire prior to collection of nasopharyngeal/throat swab samples and blood samples tested for SARS-CoV-2 RNA (DaAn Gene, China) and anti-SARS-CoV-2 IgM/IgG antibodies (commercial lateral flow immunoassays), respectively. Univariable and multivariable logistic regression analysis were used to analyze associated factors. None of 1,651 participants were found positive for SARS-CoV-2 RNA (0%, 95% confidence intervals, CI: 0-0.2). Fourteen were positive for anti-SARS-CoV-2 IgM/IgG antibodies (0.9%, 95% CI: 0.5-1.4), including 7 positives for IgM and 7 positives for IgG (0.4%, 95% CI: 0.2-0.9). Being over 50 years old was independently associated with virus exposure (OR: 5.8, 95% CI: 1.0-32.1%, p = 0.045). Despite high exposure risk, no current infection was found, and a very high proportion was still susceptible to SARS-CoV-2 infection and would clearly benefit from vaccination. Continuing active surveillance, rolling out of vaccination and monitoring response to vaccine will help better control the COVID-19 spread. specialized THAILANDE 052 050 17 2 e0263127 [12 ] 2022 1932-6203 https://www.documentation.ird.fr/hor/fdi:010084610 10.1371/journal.pone.0263127 1932-6203 [F B010084610] https://www.documentation.ird.fr/hor/fdi:010084610 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2022-05/010084610.pdf IRD - Base Horizon / Pleins textes 2022-05-04 2025-02-24 fdi:010084610 fre