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Associations between Wearing Masks, Washing Hands, and Social Distancing Practices, and Risk of COVID-19 Infection in Public: A Cohort-Based Case-Control Study in Thailand

37 Pages Posted: 14 Aug 2020

See all articles by Pawinee Doung-ngern

Pawinee Doung-ngern

Ministry of Public Health, Thailand - Department of Disease Control

Repeepong Suphanchaimat

Department of Disease Control, Ministry of Public Health

Apinya Panjangampatthana

Department of Disease Control, Ministry of Public Health

Chawisar Janekrongtham

Department of Disease Control, Ministry of Public Health

Duangrat Ruampoom

Department of Disease Control, Ministry of Public Health

Nawaporn Daochaeng

Department of Disease Control, Ministry of Public Health

Napatchakorn Eungkanit

Department of Disease Control, Ministry of Public Health

Nichakul Pisitpayat

Department of Disease Control, Ministry of Public Health

Nuengruethai Srisong

Department of Disease Control, Ministry of Public Health

Oiythip Yasopa

Department of Disease Control, Ministry of Public Health

Patchanee Plernprom

Department of Disease Control, Ministry of Public Health

Pitiphon Promduangsi

Department of Disease Control, Ministry of Public Health

Panita Kumphon

Department of Disease Control, Ministry of Public Health

Paphanij Suangtho

Department of Disease Control, Ministry of Public Health

Peeriya Watakulsin

Department of Disease Control, Ministry of Public Health

Sarinya Chaiya

Department of Disease Control, Ministry of Public Health

Somkid Kripattanapong

Department of Disease Control, Ministry of Public Health

Thanawadee Chantian

Department of Disease Control, Ministry of Public Health

Chawetsan Namwat

Department of Disease Control, Ministry of Public Health

Direk Limmathurotsakul

Mahidol University - Mahidol-Oxford Tropical Medicine Research Unit

More...

Abstract

Background: Effectiveness of personal protective measure against COVID-19 infection is largely unknown.  

Methods: We conducted a retrospective case-control study, using a cohort of contact tracing records in Thailand. A total of 1,050 asymptomatic contacts of COVID-19 patients between 1 and 31 March 2020 were retrospectively interviewed by phone about their protective measures against COVID-19 infection. Cases were defined as asymptomatic contacts who were diagnosed with COVID-19 by 21 April 2020. Multilevel mixed-effect logistic regression models were used  

Findings: Overall, 211 (20%) were diagnosed with COVID-19 by 21 Apr 2020 (case group) while 839 (80%) were not (control group). Fourteen percent of cases (29/210) and 24% of controls (198/823) reported wearing either non-medical or medical masks all the time during the contact period. Wearing masks all the time (adjusted odds ratio [aOR] 0.23; 95%CI 0.09-0.60) was independently associated with lower risk of COVID-19 infection compared to not wearing masks, while wearing masks sometimes (aOR 0.87; 95%CI 0.41-1.84) was not. Shortest distance of contact >1 meter (aOR 0.15; 95%CI 0.04-0.63), duration of close contact ≤15 minutes (aOR 0.24; 95%CI 0.07-0.90) and washing hands often (aOR 0.33; 95%CI 0.13-0.87) were significantly associated with lower risk of infection. Sharing a cigarette (aOR 3.47; 95%CI 1.09-11.02) was associated with higher risk of infection. Those who wore masks all the time were more likely to wash hands and practice social distancing. We estimated that if everyone wore a mask all the time, washed hands often, did not share a dish, cup or cigarette, maintained distances >1 meter and spent ≤15 minutes with close contacts, cases would have been reduced by 84%.      

Interpretation: Our findings support consistently wearing masks, washing hands, and social distancing in public to protect against COVID-19 infections. Combining measures could substantially reduce infections in Thailand.

Funding Statement: The study was supported by the DDC, MoPH, Thailand. DL is supported by the Wellcome Trust (106698/Z/14/Z).

Declaration of Interests: The authors declare no competing interests.

Ethics Approval Statement: As this study was part of the routine situation analysis and outbreak investigation of the DDC MoPH Thailand, it was not required to obtain ethics approval and no written informed consent was collected. However, the study team strictly followed ethical standards in research; that is, all individual information was strictly kept confidential and not reported in the paper. The DDC MoPH Thailand approved the analysis and reporting of data in aggregate.

Keywords: COVID-19; SARS-CoV-2; mask; medical mask; non-medical mask; hand washing; social distancing; Contact Tracing

Suggested Citation

Doung-ngern, Pawinee and Suphanchaimat, Repeepong and Panjangampatthana, Apinya and Janekrongtham, Chawisar and Ruampoom, Duangrat and Daochaeng, Nawaporn and Eungkanit, Napatchakorn and Pisitpayat, Nichakul and Srisong, Nuengruethai and Yasopa, Oiythip and Plernprom, Patchanee and Promduangsi, Pitiphon and Kumphon, Panita and Suangtho, Paphanij and Watakulsin, Peeriya and Chaiya, Sarinya and Kripattanapong, Somkid and Chantian, Thanawadee and Namwat, Chawetsan and Limmathurotsakul, Direk, Associations between Wearing Masks, Washing Hands, and Social Distancing Practices, and Risk of COVID-19 Infection in Public: A Cohort-Based Case-Control Study in Thailand (6/18/2020). Available at SSRN: https://ssrn.com/abstract=3633162 or http://dx.doi.org/10.2139/ssrn.3633162

Pawinee Doung-ngern

Ministry of Public Health, Thailand - Department of Disease Control ( email )

Nonthaburi
Thailand

Repeepong Suphanchaimat

Department of Disease Control, Ministry of Public Health

Apinya Panjangampatthana

Department of Disease Control, Ministry of Public Health

Chawisar Janekrongtham

Department of Disease Control, Ministry of Public Health

Duangrat Ruampoom

Department of Disease Control, Ministry of Public Health

Nawaporn Daochaeng

Department of Disease Control, Ministry of Public Health

Napatchakorn Eungkanit

Department of Disease Control, Ministry of Public Health

Nichakul Pisitpayat

Department of Disease Control, Ministry of Public Health

Nuengruethai Srisong

Department of Disease Control, Ministry of Public Health

Oiythip Yasopa

Department of Disease Control, Ministry of Public Health

Patchanee Plernprom

Department of Disease Control, Ministry of Public Health

Pitiphon Promduangsi

Department of Disease Control, Ministry of Public Health

Panita Kumphon

Department of Disease Control, Ministry of Public Health

Paphanij Suangtho

Department of Disease Control, Ministry of Public Health

Peeriya Watakulsin

Department of Disease Control, Ministry of Public Health

Sarinya Chaiya

Department of Disease Control, Ministry of Public Health

Somkid Kripattanapong

Department of Disease Control, Ministry of Public Health

Thanawadee Chantian

Department of Disease Control, Ministry of Public Health

Chawetsan Namwat

Department of Disease Control, Ministry of Public Health

Direk Limmathurotsakul (Contact Author)

Mahidol University - Mahidol-Oxford Tropical Medicine Research Unit ( email )

Thailand

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