Background 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 SARS-CoV-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.

Objectives We estimated influenza-like symptom (ILS) incidence among healthcare personnel (HCP) in four hospitals and the economic impact due to ILS in the Thai HCP population during July 2020–June 2021 (Thailand’s expected 2020 influenza season), which also coincided with the novel coronavirus disease 2019 pandemic. Methods We followed HCP, in a prospective observational cohort, weekly for ≥1 of: muscle pain, cough, runny nose/nasal congestion, sore throat, or difficulty breathing. We fitted population-averaged Poisson regression models to identify factors associated with acquiring ILS and to calculate ILS incidence. We applied epidemiologic parameters to Thailand’s HCP population (227 349 persons) to estimate economic impact. Results Of 2184 participants, adjusted all-cause ILS incidence was 6.1 episodes per 100 person-years (95% confidence interval 3.4–10.9). Among Thailand’s HCP population, 13 909 ILS episodes were estimated to occur annually and would result in US$235 135 economic loss. Controlling for study site and calendar month, factors associated with acquiring ≥1 ILS versus no ILS included being female, having asthma, and using personal protective equipment ‘frequently, but not always’. Conclusions All-cause ILS resulted in considerable economic loss among Thai HCP workforce. These findings underscore the importance of public health interventions to reduce the risk of acquiring ILS.