Which Masks Work Best?

By now, there is pretty widespread agreement by infectious disease experts, researchers and those who believe in science that wearing masks can help prevent the transmission of the coronavirus, and ultimately save lives. (Here is a previous post I wrote about this if you’d like to see the research. Link to post)

Countries that have adopted mask wearing and combined it with contact tracing and organized testing have been quite successful in minimizing the spread of COVID-19 in their populations. Countries who have not done this (like the US) are seeing the consequences of not wearing masks on both local and national levels.

One problem that remains, even for those who do wear masks is which type of masks actually work. There is no agreed upon standard and definitive measure of protection that various types of masks offer.

No Agreed Upon Standard

This maybe changing. A recent article in the Washington Post (https://www.washingtonpost.com/business/2020/10/20/face-mask-coronavirus-standards/) examines how consumer masks may soon come with labels that identify how well they work. Since the start of the pandemic the market for masks has been pretty much of a wild West of different available choices.

Sometimes fashion and design are given more weight than actual efficacy. The personal protective equipment industry is trying to bring some clarity to this issue by creating a uniform set of standards that will show how well different types of masks protect people and those around them.

All this chaos came from the initial scramble at the beginning of the pandemic to get enough masks to frontline workers who needed them. There was an immediate shortage of surgical masks and the more protective respirator type masks (often worn by construction workers).

The result was that many people had to resort to DIY solutions. Homemade masks, obviously, can not be tested in a laboratory, so it’s pretty much impossible to know which types of masks are most effective in stopping the transmission of the virus.

Laboratory Tests on Mask Effectiveness

Fortunately, however, there have been some studies done that have evaluated how different masks work. 

According to a recent study from Duke University looked at 14 different mask designs and materials. (https://hartfordhealthcare.org/about-us/news-press/news-detail?articleid=27691&publicId=395).

A meta-analysis of all studies on masks from the US, Germany and China was done by the Institute of Health Metrics and Evaluation (IHME) from Washington University, a research center that has provided projections on hospitalizations and deaths during the COVID-19 pandemic, 

They found that if 95 percent of people wear cloth masks when within 6 feet of other people in public, it will reduce COVID-19 transmission by at least 30 percent. So if every infected person transmits the virus to 30 percent fewer people, it improves the chances of subduing COVID-19’s spread in the United States.

The assumption here is that most people wear cloth masks. The Duke University studied looked at a variety of cloth mask designs as well as surgical masks and N95 respirators. They tested the masks by using a cardboard box with a lens, a laser and a phone’s camera to track particles released from a person’s mouth when speaking.

Test subjects were asked to repeat the same phrase into the box without a mask, then repeat with each mask. Every mask was tested 10 times. What they found might surprise you. Three of the top four masks were cotton.