Here's How To Think About The Danish Mask Study

[Julieanne]

Vinay Prasad, MD, MPH
November 18, 2020

What the DANMASK-19 trial showed and didn't show about mask use and COVID-19

I was drawn to science and medicine because of all human endeavors, ours is one where smart people can say, "I don't know." We don't stop there. We run a study or experiment that helps us know more. That is what makes what we do different than other human endeavors.
I start then with a humility as I take on the Danish Mask Study, published on Wednesday in the Annals of Internal Medicine. This is a 4,800-person randomized trial that took place in the spring and early summer in Denmark. The trial was run at a time where most Danes did not wear masks when they left their house. It told participants to practice social distancing and randomly assigned them with the advice to wear a mask (and even gave them 50 surgical masks), advising them to change it after every 8 hours of use, or gave them no advice to wear mask, and followed them to see how many acquired SARS-CoV-2 by PCR or antibody testing.

Read more: https://www.medpagetoday.com/blogs/v..._medium=email&

Here is the study: https://www.rigshospitalet.dk/englis...g-SARS-Co.aspx

[Islander]

In other words, the study was inconclusive. The numbers emerging from US cities who do/do not mandate masks seem to show clear evidence that masks cut virus transmission by a significant margin… But that may just be my interpretation.