Prevalences of SARS-CoV-2 RNA and anti-SARS-CoV-2 among at-risk populations in Chiang Mai and Lamphun provinces, Thailand, during November 2020–January 2021

Abstract

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.

Health-Risk Behaviors, COVID-19 Preventive Behaviors, and the Impact of the COVID-19 Pandemic on the Working-Age Population of Bangkok, Thailand

“…Additionally, the emphasis on the severity of the disease and the impact of COVID-19 infection on their health and life encouraged working adults to adopt appropriate disease prevention behaviors to enable them to continue working [ 19 , 20 ]. Our results also showed that most respondents had a high level of compliance with the DMHTT measures, suggesting that strict adherence to government policies and disease prevention practices is accepted as part of daily life [ 21 , 22 , 23 ].…”

Factors Predicting the Coronavirus Disease 2019 Preventive Behaviors of Older Adults: A Cross-Sectional Study in Bangkok, Thailand

“…Furthermore, vaccinations were an important tool in managing COVID-19, including reducing the cases of severe illness and death, as evidenced by the fact that 76.0% of the study participants had been injected with a COVID-19 vaccine, and that 73.8% intended to be vaccinated against COVID-19 when notified by the public health officials in the places where they were registered. Most of the participants (86.0%) had high compliance with the DMHTT measures, complying with such measures regularly and accepting disease prevention practices as part of their daily lives [ 24 , 25 ].…”

SARS-CoV-2 Seroprevalence in Unvaccinated Adults in Thailand in November 2021

“…In Thailand, serological studies were conducted before the delta wave. A study among non-healthcare workers with a high potential of exposure to SARS-CoV-2 in the northern regions (the Chiang Mai and Lamphun provinces) during the second wave of the outbreak (November 2020-January 2021) reported 0.9% (n = 1651) positive results for antibody tests [10]. Another study in healthcare workers in the Bangkok metropolitan area, and the western and eastern regions of Thailand from January to March 2021 reported that the positive rate for SARS-Cov-2 IgG-spike antibodies was 0.2% (n = 600) [11].…”