October 15, 2021: The Impact of Community Masking on COVID-19: A Cluster-Randomized Trial in Bangladesh (Jason Abaluck, PhD)

Posted on by terren.green@duke.edu

Speaker

Jason Abaluck, PhD
Professor of Economics
Yale School of Management

Topic

The Impact of Community Masking on COVID-19: A Cluster-Randomized Trial in Bangladesh

Keywords

COVID-19; Cluster-randomized trial; Masking; Community spread; NORM model

Key Points

  • Dr. Abaluck’s cluster-randomized trial on the impact of community masking in ~350,000 adults in 600 villages of Bangledesh aimed to answer 2 questions: What strategies or interventions will increase mask-wearing? and What is the impact of mask wearing intervention on COVID-10?
  • There are two major differences between the existing randomized trials of mask wearing for flu and the impact of community masking in Bangladesh trial. The first issue is the existing trials were randomized individually not by communities so you cannot evaluate weather masks act as source control. The second issue with the existing trials is the discrepancy between the number of people who attest to wearing a mask and the number who actually wore a mask.
  • The impact of community masking in Bangladesh trial used the NORM model to increase mask wearing. The NORM model distributes masks at No-cost, Offers information about why mask wearing is important, Reinforces mask wearing by having mask promoters give free masks and information in public places, and Modeling by trusted community leaders wearing masks and endorsing mask wearing.
  • The NORM model more than tripled mask usage(13% usage increased to 42%), increased physical distancing, and had a sustained impact that lasted at least 10 weeks.
  • Communities where the NORM model was employed saw a 9% reduction in symptomatic COVID-19 infections.
  • Mask wearing showed a greater reduction in COVID-19 among the elderly.

Discussion Themes

The NORM model would have different efficacy rates in different cultures and communities.

You can get some people to wear a mask by just distributing the masks in public places and asking them to wear them.

Masks are not an all-or-nothing protection. Masks have a dose-reduction effect and that dose-reduction translates into a transmission effect.

 

Read more about the Dr. Abaluck’s work on masking and COVID-19 in the recently published Discussion Paper.

Tags

#pctGR, @Collaboratory1, @Jabaluck