Impact of community masking on COVID-19: A cluster-randomized trial in Bangladesh

Jason Abaluck, Laura H Kwong, Ashley Styczynski, Ashraful Haque, Md Alamgir Kabir, Ellen Bates-Jefferys, Emily Crawford, Jade Benjamin-Chung, Shabib Raihan, Shadman Rahman, Salim Benhachmi, Neeti Zaman Bintee, Peter J Winch, Maqsud Hossain, Hasan Mahmud Reza, Abdullah All Jaber, Shawkee Gulshan Momen, Aura Rahman, Faika Laz Banti, Tahrima Saiha Huq, Stephen P Luby, Ahmed Mushfiq Mobarak, Jason Abaluck, Laura H Kwong, Ashley Styczynski, Ashraful Haque, Md Alamgir Kabir, Ellen Bates-Jefferys, Emily Crawford, Jade Benjamin-Chung, Shabib Raihan, Shadman Rahman, Salim Benhachmi, Neeti Zaman Bintee, Peter J Winch, Maqsud Hossain, Hasan Mahmud Reza, Abdullah All Jaber, Shawkee Gulshan Momen, Aura Rahman, Faika Laz Banti, Tahrima Saiha Huq, Stephen P Luby, Ahmed Mushfiq Mobarak

Abstract

We conducted a cluster-randomized trial to measure the effect of community-level mask distribution and promotion on symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in rural Bangladesh from November 2020 to April 2021 (N = 600 villages, N = 342,183 adults). We cross-randomized mask type (cloth versus surgical) and promotion strategies at the village and household level. Proper mask-wearing increased from 13.3% in the control group to 42.3% in the intervention arm (adjusted percentage point difference = 0.29; 95% confidence interval = [0.26, 0.31]). The intervention reduced symptomatic seroprevalence (adjusted prevalence ratio = 0.91 [0.82, 1.00]), especially among adults ≥60 years old in villages where surgical masks were distributed (adjusted prevalence ratio = 0.65 [0.45, 0.85]). Mask distribution with promotion was a scalable and effective method to reduce symptomatic SARS-CoV-2 infections.

Trial registration: ClinicalTrials.gov NCT04630054.

Figures

Impact of intervention on mask use and…
Impact of intervention on mask use and biological outcomes.
The figure shows the raw means of mask-wearing (left), COVID-19 symptoms (middle), and symptomatic seropositivity (right) in the control and treatment arms. The estimated change in each outcome, confidence intervals, and p values adjust for preregistered covariates (and thus are not computable from the raw values). Individuals who were symptomatic but did not consent to blood collection were dropped from the sample; measured symptomatic seropositivity thus understates the true fraction of the population that was symptomatic seropositive.
Fig. 1.. Map of 600 treatment and…
Fig. 1.. Map of 600 treatment and control unions.
The figure shows the location of the 600 treatment and control unions in the study. RCT, randomized controlled trial; 1 mile = 1.6 km.

References

    1. Howard J., Huang A., Li Z., Tufekci Z., Zdimal V., van der Westhuizen H.-M., von Delft A., Price A., Fridman L., Tang L.-H., Tang V., Watson G. L., Bax C. E., Shaikh R., Questier F., Hernandez D., Chu L. F., Ramirez C. M., Rimoin A. W., An evidence review of face masks against COVID-19. Proc. Natl. Acad. Sci. U.S.A. 118, e2014564118 (2021). 10.1073/pnas.2014564118
    1. Leung N. H. L., Chu D. K. W., Shiu E. Y. C., Chan K.-H., McDevitt J. J., Hau B. J. P., Yen H.-L., Li Y., Ip D. K. M., Peiris J. S. M., Seto W.-H., Leung G. M., Milton D. K., Cowling B. J., Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat. Med. 26, 676–680 (2020). 10.1038/s41591-020-0843-2
    1. MacIntyre C. R., Chughtai A. A., Facemasks for the prevention of infection in healthcare and community settings. BMJ 350, h694 (2015). 10.1136/bmj.h694
    1. Bundgaard H., Bundgaard J. S., Raaschou-Pedersen D. E. T., von Buchwald C., Todsen T., Norsk J. B., Pries-Heje M. M., Vissing C. R., Nielsen P. B., Winsløw U. C., Fogh K., Hasselbalch R., Kristensen J. H., Ringgaard A., Porsborg Andersen M., Goecke N. B., Trebbien R., Skovgaard K., Benfield T., Ullum H., Torp-Pedersen C., Iversen K., Effectiveness of adding a mask recommendation to other public health measures to prevent SARS-CoV-2 infection in Danish mask wearers: A randomized controlled trial. Ann. Intern. Med. 174, 335–343 (2021). 10.7326/M20-6817
    1. Ngonghala C. N., Iboi E., Eikenberry S., Scotch M., MacIntyre C. R., Bonds M. H., Gumel A. B., Mathematical assessment of the impact of non-pharmaceutical interventions on curtailing the 2019 novel Coronavirus. Math. Biosci. 325, 108364 (2020). 10.1016/j.mbs.2020.108364
    1. Leffler C. T., Ing E., Lykins J. D., Hogan M. C., McKeown C. A., Grzybowski A., Association of country-wide coronavirus mortality with demographics, testing, lockdowns, and public wearing of masks. Am. J. Trop. Med. Hyg. 103, 2400–2411 (2020). 10.4269/ajtmh.20-1015
    1. Lyu W., Wehby G. L., Community use of face masks and COVID-19: Evidence from a natural experiment of state mandates in the US. Health Aff. 39, 1419–1425 (2020). 10.1377/hlthaff.2020.00818
    1. Chernozhukov V., Kasahara H., Schrimpf P., Causal impact of masks, policies, behavior on early covid-19 pandemic in the U.S. J. Econom. 220, 23–62 (2021). 10.1016/j.jeconom.2020.09.003
    1. Abaluck J., Chevalier J. A., Christakis N. A., Forman H. P., Kaplan E. H., Ko A., Vermund S. H., The case for universal cloth mask adoption and policies to increase supply of medical masks for health workers. SSRN 3567438 [Preprint] (2020); 10.2139/ssrn.3567438
    1. Cheng Y., Ma N., Witt C., Rapp S., Wild P. S., Andreae M. O., Pöschl U., Su H., Face masks effectively limit the probability of SARS-CoV-2 transmission. Science 372, 1439–1443 (2021). 10.1126/science.abg6296
    1. A. Mullard, “How COVID vaccines are being divvied up around the world,” Nature News, 30 November 2020.
    1. T. A. Ghebreyesus, WHO Director-General’s opening remarks at the media briefing on COVID-19 - 5 June 2020 (World Health Organization, 2020).
    1. L. M. Brosseau, M. Sietsema, “Commentary: Masks-for-all for COVID-19 not based on sound data” (Center for Infectious Disease Research and Policy, University of Minnesota, 2020); .
    1. Johansson M. A., Quandelacy T. M., Kada S., Prasad P. V., Steele M., Brooks J. T., Slayton R. B., Biggerstaff M., Butler J. C., SARS-CoV-2 transmission from people without COVID-19 symptoms. JAMA Netw. Open 4, e2035057 (2021). 10.1001/jamanetworkopen.2020.35057
    1. Centers for Disease Control and Prevention (CDC), “Science brief: Community use of cloth masks to control the spread of SARS-CoV-2” (CDC, 2021).
    1. J. M. Brophy, “Covid-19: Controversial trial may actually show that masks protect the wearer,” BMJ Opinion, 24 November 2020.
    1. Pan J., Harb C., Leng W., Marr L. C., Inward and outward effectiveness of cloth masks, a surgical mask, and a face shield. Aerosol Sci. Technol. 55, 718–733 (2021). 10.1080/02786826.2021.1890687
    1. Kahneman D., Miller D. T., Norm theory: Comparing reality to its alternatives. Psychol. Rev. 93, 136–153 (1986). 10.1037/0033-295X.93.2.136
    1. Jordan J., Yoeli E., Rand D., Don’t get it or don’t spread it: Comparing self-interested versus prosocial motivations for COVID-19 prevention behaviors. PsyArXiv [Preprint] (2020); 10.31234/
    1. Cialdini R. B., Goldstein N. J., Social influence: Compliance and conformity. Annu. Rev. Psychol. 55, 591–621 (2004). 10.1146/annurev.psych.55.090902.142015
    1. Bates M., Glennerster R., Gumede K., Duflo E., The price is wrong. Field Actions Sci. Rep. 4, 30 (2012).
    1. A. Karing, “Social signaling and childhood immunization: A field experiment in Sierra Leone,” Working paper, University of California, Berkeley (2018).
    1. Karlan D., McConnell M., Mullainathan S., Zinman J., Getting to the top of mind: How reminders increase saving. Manage. Sci. 62, 3393–3411 (2016). 10.1287/mnsc.2015.2296
    1. Goldstein N. J., Cialdini R. B., Griskevicius V., A room with a viewpoint: Using social norms to motivate environmental conservation in hotels. J. Consum. Res. 35, 472–482 (2008). 10.1086/586910
    1. Miller G., Mobarak A. M., Learning about new technologies through social networks: Experimental evidence on nontraditional stoves in Bangladesh. Mark. Sci. 34, 480–499 (2014). 10.1287/mksc.2014.0845
    1. Manchanda P., Xie Y., Youn N., The role of targeted communication and contagion in product adoption. Mark. Sci. 27, 961–976 (2008). 10.1287/mksc.1070.0354
    1. C. Bicchieri, Norms in the Wild: How to Diagnose, Measure, and Change Social Norms (Oxford Univ. Press, 2016).
    1. Bhuiyan T. R., Hulse J. D., Hegde S. T., Akhtar M., Islam M. T., Khan Z. H., Khan I. I., Ahmed S., Rashid M. M., Rashid R., Gurley E. S., Shirin T., Khan A. I., Azman A. S., Qadri F., SARS-CoV-2 seroprevalence in Chattogram, Bangladesh before the Delta surge, March-June 2021. medRxiv 2021.07.16.21260611 [Preprint] (2021); 10.1101/2021.07.16.21260611
    1. icddr,b, “Higher covid-19 seropositivity observed among residents in Dhaka and Chattogram,” 22 June 2021; .
    1. Management Information System (MIS), Directorate General of Health Services (DGHS), COVID-19 dynamic dashboard for Bangladesh (2021); [accessed 16 August 2021].
    1. Murhekar M. V., Bhatnagar T., Thangaraj J. W. V., Saravanakumar V., Kumar M. S., Selvaraju S., Rade K., Kumar C. P. G., Sabarinathan R., Turuk A., Asthana S., Balachandar R., Bangar S. D., Bansal A. K., Chopra V., Das D., Deb A. K., Devi K. R., Dhikav V., Dwivedi G. R., Khan S. M. S., Kumar M. S., Laxmaiah A., Madhukar M., Mahapatra A., Rangaraju C., Turuk J., Yadav R., Andhalkar R., Arunraj K., Bharadwaj D. K., Bharti P., Bhattacharya D., Bhat J., Chahal A. S., Chakraborty D., Chaudhury A., Deval H., Dhatrak S., Dayal R., Elantamilan D., Giridharan P., Haq I., Hudda R. K., Jagjeevan B., Kalliath A., Kanungo S., Krishnan N. N., Kshatri J. S., Kumar A., Kumar N., Kumar V. G. V., Lakshmi G. G. J. N., Mehta G., Mishra N. K., Mitra A., Nagbhushanam K., Nimmathota A., Nirmala A. R., Pandey A. K., Prasad G. V., Qurieshi M. A., Reddy S. D., Robinson A., Sahay S., Saxena R., Sekar K., Shukla V. K., Singh H. B., Singh P. K., Singh P., Singh R., Srinivasan N., Varma D. S., Viramgami A., Wilson V. C., Yadav S., Yadav S., Zaman K., Chakrabarti A., Das A., Dhaliwal R. S., Dutta S., Kant R., Khan A. M., Narain K., Narasimhaiah S., Padmapriyadarshini C., Pandey K., Pati S., Patil S., Rajkumar H., Ramarao T., Sharma Y. K., Singh S., Panda S., Reddy D. C. S., Bhargava B., ICMR Serosurveillance Group , SARS-CoV-2 seroprevalence among the general population and healthcare workers in India, December 2020-January 2021. Int. J. Infect. Dis. 108, 145–155 (2021). 10.1016/j.ijid.2021.05.040
    1. A. Anand, J. Sandefur, A. Subramanian, “Three new estimates of India’s all-cause excess mortality during the COVID-19 pandemic,” Working paper no. 589, Center for Global Development, July 2021.
    1. J. Abaluck, A. M. Mobarak, “Getting all Bangladeshis to wear masks,” WhiteBoard Magazine, 1 December 2020.
    1. Jakubowski A., Egger D., Nekesa C., Lowe L., Walker M., Miguel E., Self-reported mask wearing greatly exceeds directly observed use: Urgent need for policy intervention in Kenya. medRxiv 2021.01.27.21250487 [Preprint] (2021); .10.1101/2021.01.27.21250487
    1. K. K. Tithila, “Brac’s efforts to mask up Bangladesh could be game-changer,” Dhaka Tribune (Bangladesh), 15 July 2021.
    1. S. Riaz, “Punjab authorities kick off ‘NORM’ campaign to increase mask-wearing,” Arab New (Pakistan), 30 June 2021.
    1. S. Bhattacharjee, “Covid-19 Crisis: India draws lessons from Bangladesh’s mask study,” Business Standard (India), 15 May 2021.
    1. Republica, “Nepal Mask Campaign launches with the slogan ‘Let’s wear masks, let’s save each other’s lives’,” myRepública, 16 August 2021).
    1. Hollands G. J., Carter P., Answer S., King S. E., Jebb S. A., Ogilvie D., Shemilt I., Higgins J. P. T., Marteau T. M., Altering the availability or proximity of food, alcohol, and tobacco products to change their selection and consumption. Cochrane Database Syst. Rev. 2019, CD012576 (2019). 10.1002/14651858.CD012573.pub3
    1. Naikoba S., Hayward A., The effectiveness of interventions aimed at increasing handwashing in healthcare workers – a systematic review. J. Hosp. Infect. 47, 173–180 (2001). 10.1053/jhin.2000.0882
    1. Houghton C., Meskell P., Delaney H., Smalle M., Glenton C., Booth A., Chan X. H. S., Devane D., Biesty L. M., Barriers and facilitators to healthcare workers’ adherence with infection prevention and control (IPC) guidelines for respiratory infectious diseases: A rapid qualitative evidence synthesis. Cochrane Database Syst. Rev. 4, CD013582 (2020). 10.1002/14651858.CD013582
    1. Seo H. J., Sohng K.-Y., Chang S. O., Chaung S. K., Won J. S., Choi M.-J., Interventions to improve hand hygiene compliance in emergency departments: A systematic review. J. Hosp. Infect. 102, 394–406 (2019). 10.1016/j.jhin.2019.03.013
    1. Biswas D., Ahmed M., Roguski K., Ghosh P. K., Parveen S., Nizame F. A., Rahman M. Z., Chowdhury F., Rahman M., Luby S. P., Sturm-Ramirez K., Iuliano A. D., Effectiveness of a behavior change intervention with hand sanitizer use and respiratory hygiene in reducing laboratory-confirmed influenza among schoolchildren in Bangladesh: A cluster randomized controlled trial. Am. J. Trop. Med. Hyg. 101, 1446–1455 (2019). 10.4269/ajtmh.19-0376
    1. McGuinness S. L., Barker S. F., O’Toole J., Cheng A. C., Forbes A. B., Sinclair M., Leder K., Effect of hygiene interventions on acute respiratory infections in childcare, school and domestic settings in low- and middle-income countries: A systematic review. Trop. Med. Int. Health 23, 816–833 (2018). 10.1111/tmi.13080
    1. Guiteras R., Levinsohn J., Mobarak A. M., Sanitation subsidies. Encouraging sanitation investment in the developing world: A cluster-randomized trial. Science 348, 903–906 (2015). 10.1126/science.aaa0491
    1. Patil S. R., Arnold B. F., Salvatore A. L., Briceno B., Ganguly S., Colford J. M. Jr., Gertler P. J., The effect of India’s total sanitation campaign on defecation behaviors and child health in rural Madhya Pradesh: A cluster randomized controlled trial. PLOS Med. 11, e1001709 (2014). 10.1371/journal.pmed.1001709
    1. Solís Arce J. S., Warren S. S., Meriggi N. F., Scacco A., McMurry N., Voors M., Syunyaev G., Malik A. A., Aboutajdine S., Adeojo O., Anigo D., Armand A., Asad S., Atyera M., Augsburg B., Awasthi M., Ayesiga G. E., Bancalari A., Björkman Nyqvist M., Borisova E., Bosancianu C. M., Cabra García M. R., Cheema A., Collins E., Cuccaro F., Farooqi A. Z., Fatima T., Fracchia M., Galindo Soria M. L., Guariso A., Hasanain A., Jaramillo S., Kallon S., Kamwesigye A., Kharel A., Kreps S., Levine M., Littman R., Malik M., Manirabaruta G., Mfura J. L. H., Momoh F., Mucauque A., Mussa I., Nsabimana J. A., Obara I., Otálora M. J., Ouédraogo B. W., Pare T. B., Platas M. R., Polanco L., Qureshi J. A., Raheem M., Ramakrishna V., Rendrá I., Shah T., Shaked S. E., Shapiro J. N., Svensson J., Tariq A., Tchibozo A. M., Tiwana H. A., Trivedi B., Vernot C., Vicente P. C., Weissinger L. B., Zafar B., Zhang B., Karlan D., Callen M., Teachout M., Humphreys M., Mobarak A. M., Omer S. B., COVID-19 vaccine acceptance and hesitancy in low- and middle-income countries. Nat. Med. 27, 1385–1394 (2021). 10.1038/s41591-021-01454-y
    1. Yan Y., Bayham J., Richter A., Fenichel E. P., Risk compensation and face mask mandates during the COVID-19 pandemic. Sci. Rep. 11, 3174 (2021). 10.1038/s41598-020-79139-8
    1. Cohen A., Einav L., Estimating risk preferences from deductible choice. Am. Econ. Rev. 97, 745–788 (2007). 10.1257/aer.97.3.745
    1. Kasting M. L., Shapiro G. K., Rosberger Z., Kahn J. A., Zimet G. D., Tempest in a teapot: A systematic review of HPV vaccination and risk compensation research. Hum. Vaccin. Immunother. 12, 1435–1450 (2016). 10.1080/21645515.2016.1141158
    1. Viscusi W. K., Masterman C. J., Income elasticities and global values of a statistical life. J. Benefit Cost Anal. 8, 226–250 (2017). 10.1017/bca.2017.12
    1. GiveWell, 2021 GiveWell cost-effectiveness analysis – Version 1 (2021); [accessed 4 January 2021].
    1. Hadfield J., Megill C., Bell S. M., Huddleston J., Potter B., Callender C., Sagulenko P., Bedford T., Neher R. A., Nextstrain: Real-time tracking of pathogen evolution. Bioinformatics 34, 4121–4123 (2018). 10.1093/bioinformatics/bty407
    1. Kwong L. H., Wilson R., Kumar S., Crider Y. S., Reyes Sanchez Y., Rempel D., Pillarisetti A., Review of the breathability and filtration efficiency of common household materials for face masks. ACS Nano 15, 5904–5924 (2021). 10.1021/acsnano.0c10146
    1. Duncan S., Bodurtha P., Naqvi S., The protective performance of reusable cloth face masks, disposable procedure masks, KN95 masks and N95 respirators: Filtration and total inward leakage. PLOS ONE 16, e0258191 (2021). 10.1371/journal.pone.0258191
    1. Fadare O. O., Okoffo E. D., Covid-19 face masks: A potential source of microplastic fibers in the environment. Sci. Total Environ. 737, 140279 (2020). 10.1016/j.scitotenv.2020.140279
    1. Environment and Social Development Organization (ESDO), “COVID-19 pandemic pushes single use plastic waste outbreak: No management, no protection: High health and environmental risk unveil” (ESDO, 2020).
    1. Steensgaard I. M., Syberg K., Rist S., Hartmann N. B., Boldrin A., Hansen S. F., From macro- to microplastics – Analysis of EU regulation along the life cycle of plastic bags. Environ. Pollut. 224, 289–299 (2017). 10.1016/j.envpol.2017.02.007
    1. Jang E.-S., Kang C.-W., Do face masks become worthless after only one use in the COVID-19 pandemic? Infect. Chemother. 52, 583–591 (2020). 10.3947/ic.2020.52.4.583
    1. Kremer M., Miguel E., The illusion of sustainability. Q. J. Econ. 122, 1007–1065 (2007). 10.1162/qjec.122.3.1007
    1. van Eck P. S., Jager W., Leeflang P. S., Opinion leaders’ role in innovation diffusion: A simulation study. J. Prod. Innov. Manage. 28, 187–203 (2011). 10.1111/j.1540-5885.2011.00791.x
    1. Oster E., Thornton R., Determinants of technology adoption: Peer effects in menstrual cup take-up. J. Eur. Econ. Assoc. 10, 1263–1293 (2012). 10.1111/j.1542-4774.2012.01090.x
    1. Allcott H., Social norms and energy conservation. J. Public Econ. 95, 1082–1095 (2011). 10.1016/j.jpubeco.2011.03.003
    1. R. Guiteras, J. Levinsohn, A. M. Mobarak, “Demand estimation with strategic complementarities: Sanitation in Bangladesh,” Discussion paper no. DP13498, Centre for Economic Policy Research, January 2019).
    1. Beaman L., BenYishay A., Magruder J., Mobarak A. M., Can network theory-based targeting increase technology adoption? Am. Econ. Rev. 111, 1918–1943 (2021). 10.1257/aer.20200295
    1. Ashraf N., Bandiera O., Jack K., No margin, no mission? A field experiment on incentives for public service delivery. J. Public Econ. 120, 1–17 (2014). 10.1016/j.jpubeco.2014.06.014
    1. Chetty R., Saez E., Sandor L., What policies increase prosocial behavior? An experiment with referees at the Journal of Public Economics. J. Econ. Perspect. 28, 169–188 (2014). 10.1257/jep.28.3.169
    1. Ariely D., Bracha A., Meier S., Doing good or doing well? Image motivation and monetary incentives in behaving prosocially. Am. Econ. Rev. 99, 544–555 (2009). 10.1257/aer.99.1.544
    1. Bryan G., Karlan D., Nelson S., Commitment devices. Annu. Rev. Econ. 2, 671–698 (2010). 10.1146/annurev.economics.102308.124324
    1. Luoto J., Levine D., Albert J., Luby S., Nudging to use: Achieving safe water behaviors in Kenya and Bangladesh. J. Dev. Econ. 110, 13–21 (2014). 10.1016/j.jdeveco.2014.02.010
    1. Ashraf N., Bandiera O., Davenport E., Lee S. S., Losing prosociality in the quest for talent? Sorting, selection, and productivity in the delivery of public services. Am. Econ. Rev. 110, 1355–1394 (2020). 10.1257/aer.20180326
    1. Bursztyn L., Jensen R., Social image and economic behavior in the field: Identifying, understanding, and shaping social pressure. Annu. Rev. Econ. 9, 131–153 (2017). 10.1146/annurev-economics-063016-103625
    1. World Health Organization (WHO), WHO COVID-19 case definition (2020); [accessed on 15 October 2020].
    1. Guimarães P., Portugal P., A simple feasible procedure to fit models with high-dimensional fixed effects. Stata J. 10, 628–649 (2010). 10.1177/1536867X1101000406
    1. S. Gaure, “OLS with multiple high dimensional category dummies,” Memorandum 14/2010, Oslo University (2011).
    1. Guimarães P., Portugal P., A simple feasible procedure to fit models with high-dimensional fixed effects. Stata J. 10, 628–649 (2011). 10.1177/1536867X1101000406
    1. Zou G., A modified poisson regression approach to prospective studies with binary data. Am. J. Epidemiol. 159, 702–706 (2004). 10.1093/aje/kwh090
    1. J. Abaluck, L. H. Kwong, A. Styczynski, A. Haque, M. A. Kabir, E. Bates-Jefferys, E. Crawford, J. Benjamin-Chung, S. Raihan, S. Rahman, S. Benhachmi, N. Z. Bintee, P. J. Winch, M. Hossain, H. M. Reza, A. A. Jaber, S. Gulshan Momen, A. Rahman, F. L. Banti, T. S. Huq, S. P. Luby, A. M. Mobarak, Impact of community masking on COVID-19: A cluster-randomized trial in Bangladesh. Zenodo (2021); 10.5281/zenodo.5703876
    1. Rutterford C., Copas A., Eldridge S., Methods for sample size determination in cluster randomized trials. Int. J. Epidemiol. 44, 1051–1067 (2015). 10.1093/ije/dyv113
    1. Institute for Health Metrics and Evaluation (IHME), COVID-19 projections – Bangladesh (2021); [accessed 17 August 2021].
    1. WHO Bangladesh, COVID-19 Morbidity and Mortality Weekly Update, vol. 76, 9 August 2021; .

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