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COVID-19: Face Masks, Bangladesh

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Ashley Styczynski fitting a face mask
Ashley Styczynski fitting a face mask

“If we want to change the world, we have to be bold.” - Steve Luby

COVID-19: Can Face Masks Reduce Transmission of SARS-CoV-2 in Bangladesh? A Cluster-Randomized Controlled Trial



1.  To develop a scalable intervention that can increase consistent use  of a quality mask

2.  To assess the impact of appropriate use of high-quality masks on the spread of respiratory illnesses and especially COVID-19

3.  To assess the protective effect of masks with high filtration and breathability relative to existing face-coverings

4.  To evaluate whether increased mask use is associated with risk compensation (an increase in leaving the home or reduced compensation)



There is substantial evidence from laboratory studies that masks can reduce exhaled viral load [1], and all major public health organizations recommend that those with symptoms of COVID-19 wear masks for this reason [2]. There is also substantial evidence of asymptomatic or pre-symptomatic transmission of COVID-19 [3]. This suggests that universal adoption of cloth masks (if used regularly and properly) – including by those who appear healthy – may substantially reduce the transmission rate of the virus [4]. However, to date, there are few estimates of the degree to which mask adoption actually reduces transmission of the virus in the field. Non-experimental estimates suggest that masks lower transmission by 40-50% [5].

[1] See, for example:

Leung, N.H.L., Chu, D.K.W., Shiu, E.Y.C. et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med (2020).

Davies, A., Thompson, K.A., Giri, K., Kafatos, G., Walker, J. and Bennett, A., 2013. Testing the efficacy of homemade masks: would they protect in an influenza pandemic? Disaster medicine and public health preparedness, 7(4), pp.413-418.

Ferguson, N.M., Laydon, D., Nedjati-Gilani, G., Imai, N., Ainslie, K., Baguelin, M., Bhatia, S., Boonyasiri, A., Cucunubá, Z., Cuomo-Dannenberg, G. and Dighe, A., 2020. Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand. Imperial College, London. DOI:

Jefferson, T., Foxlee, R., Del Mar, C., Dooley, L., Ferroni, E., Hewak, B., Prabhala, A., Nair, S. and Rivetti, A., 2008. Physical interventions to interrupt or reduce the spread of respiratory viruses: systematic review. Bmj, 336(7635), pp.77-80.

Rengasamy, S., Eimer, B. and Shaffer, R.E., 2010. Simple respiratory protection—evaluation of the filtration performance of cloth masks and common fabric materials against 20–1000 nm size particles. Annals of occupational hygiene, 54(7), pp.789-798.

van der Sande, M., Teunis, P. and Sabel, R., 2008. Professional and home-made face masks reduce exposure to respiratory infections among the general population. PLoS One, 3(7).

[2] e.g. Coronavirus disease (COVID-19) advice for the public: When and how to use masks. WHO.

[3] Japanese National Institute of Infectious Diseases. Field Briefing: Diamond Princess COVID-19 Cases, 20 Feb Update. (Accessed on March 01, 2020).

[4] The gap between the laboratory evidence that masks create a partial physical barrier to viruses and the unknown extent to which masks impede transmission and illness from COVID-19 in the field stems from a variety of factors including (1) the viral exposure required for infection is not known  and (2) the relationship between viral exposure and, other things equal, the severity of illness is not known.  

[5]  Abaluck, Jason and Chevalier, Judith A. and Christakis, Nicholas A. and Forman, Howard Paul and Kaplan, Edward H. and Ko, Albert and Vermund, Sten H., The Case for Universal Cloth Mask Adoption and Policies to Increase Supply of Medical Masks for Health Workers (April 2, 2020). Available at SSRN:

Chernozhukov, Victor, Hiroyuki Kasaha, and Paul Schrimpf. "Causal impact of masks, policies, behavior on early COVID-19 pandemic in the US." arXiv preprint arXiv:2005.14168 (2020).

Lyu, Wei, and George L. Wehby. "Community Use Of Face Masks And COVID-19: Evidence From A Natural Experiment Of State Mandates In The US: Study examines impact on COVID-19 growth rates associated with state government mandates requiring face mask use in public." Health Affairs (2020): 10-1377.


Project dates

August 2020 – March 2021


Stage of work

In conjunction with the team we have selected a cloth mask design and tested cloth an surgical masks for filtration efficiency

We have conducted one pilot in 10 villages and focus group discussions to understand why mask wearing is higher in some villages than in others

Designed behavior change communication material

Plan to begin the trial in 700 villages on 22 August 2019.

Update:  18 January 2021:  The study of mask uptake and COVID-19 symptoms and sero-conversion is ongoing in 600 villages and 50 markets.



Primary Contacts:  Laura Kwong, Ashley Styczynski

Stanford University

.   Stephen Luby

.   Laura Kwong

.   Ashley Styczynski

Yale University 

.   Jason Abaluck, Associate Professor of Economics, Yale School of Management

.   Ahmed Mushfiq Mobarak, Professor of Economics

North South University, Bangladesh

.   Muhammad Maqsud Hossain, Director, Director, NSU Genome Research Institute (NGRI)

Innovations for Poverty Action (IPA)

.   Mohammad Ashraful Haque

.   Md. Alamgir Kabir