Wanitchaya KittikraisakPhunlerd PiyarajApichat VachiraphanThanapat WongrapeeSomsak PunjasamanvongTaweewun HunsawongChalinthorn SinthuwattanawiboolChaniya LeepiyasakulchaiPornsak YoocharoenEduardo Azziz-BaumgartnerJoshua A. MottSuthat ChottanapundCenters for Disease Control and PreventionArmed Forces Research Institute of Medical Sciences, ThailandThailand Ministry of Public HealthMahidol UniversityPhramongkutklao College of MedicinePhaholpolpayuhasena HospitalBamrasnaradura Infectious Diseases InstituteRayong Hospital2022-08-042022-08-042021-07-01PLoS ONE. Vol.16, No.7 July (2021)193262032-s2.0-85110169960https://repository.li.mahidol.ac.th/handle/20.500.14594/79340Background Thailand was the first country outside China to report SARS-CoV-2 infected cases. Since the detection of the first imported case on January 12th, 2020 to the time this report was written, Thailand experienced two waves of community outbreaks (March-April 2020 and December 2020-March 2021). We examined prevalence of SARS-CoV-2 seropositivity among healthcare providers (HCPs) in four hospitals approximately one year after SARSCoV- 2 first detected in Thailand. By March 2021, these hospitals have treated a total of 709 coronavirus disease 2019 (COVID-19) patients. Methods Blood specimens, collected from COVID-19 unvaccinated HCPs during January-March 2021, were tested for the presence of SARS-CoV-2 immunoglobulin G (IgG) antibodies to nucleocapsid (IgG-nucleocapsid) and spike (IgG-spike) proteins using Euroimmune® enzyme-linked immunosorbent assays. Results Of 600 HCPs enrolled, 1 (0.2%) tested positive for the SARS-CoV-2 IgG-spike antibodies, but not the IgG-nucleocapsid. Conclusion The presence of SARS-CoV-2 IgG antibodies was rare in this sample of HCPs, suggesting that this population remains susceptible to SARS-CoV-2 infection.Mahidol UniversityMultidisciplinaryArticleSCOPUS10.1371/journal.pone.0254563