Do Masks Work?

The issue of wearing masks will probably go down as one of the biggest failures in our nation’s efforts to control the pandemic. It’s a measure that was politicized early on, starting with our president and carried forward by his supporters as an issue of personal freedom. Putting aside the politics of the matter, I wanted to take a look at both the science and the data on how well masks work in controlling the current pandemic we are in. I know this is late in the game, but now that we have over 30 states with mask mandates, we have a much better dataset to look at.

Mask Efficacy

Let’s start with the science of mask efficacy. This has gone through its own roller coaster since the beginning of pandemic, with each twist and turn caused by some nuance on the issue. At the start of the pandemic, our nation had a PPE shortage and masks of any kind were hard to come by, much less the kind needed by health care workers dealing with COVID-19 patients in hospitals or first responders answering calls to unknown situations.

In the early weeks of the pandemic, it was unclear how the virus was transmitted from human to human. At that time, the guidance was that only those treating or caring for an infected individual should wear a mask. Much of that guidance was to hopefully prevent panic buying of masks during the shortage. Was that a wise decision? It’s hard to say, particularly when there was no clear indication of when the PPE shortage would be alleviated.

Then came the issue of how effective masks were in protecting an individual. The focus was on the receiver and some early research showed that mask efficacy was only about 15% for the receiver. However, as the science evolved in studying the efficacy of masks, it became apparent that to really control spread of the coronavirus, the aerosols and droplets from the transmitter or infected person was the key factor.

Studies showed that if an infected person wore a mask, up to 85% of the infectious particles could be contained, protecting others around the person. An extensive study published by a group of researchers in Science Partner Journals provided evidence of such protection.


A recent study by Duke University to help school districts determine the best and most cost effective mask to purchase for staff found that even cloth masks helped reduce the transmission of coronavirus by a significant amount. That study also found that gaiters were the least effective in reducing the spread of the virus.

Masks in Public

While the studies provide the scientific evidence of mask efficacy, the real proof is when the public adopts the practice in helping curb the spread of the virus. Even though the US was reticent in adopting masks as a part of public life, other countries embraced the protective measure, some more quickly than others.

Masks have always been a part of the culture in Asia, particularly in Japan and China. The Chinese wore masks during the days when their cities were struggling with pollution. In Japan, the polite culture encouraged people to wear masks when sick to protect others. How novel a notion in this day and age.

To provide more perspective on this, someone wrote in Psychology Today about the Asian practice of wearing masks. “Fast forward to 2010 when I lived in Tokyo again. Right away, I noticed that medical masks had become ubiquitous. And when I traveled to other countries in Asia, such as South Korea, China, Thailand, and Malaysia, it seemed that many more people were wearing them than decades before. When I asked, I was again told that people wore them when they were sick, to protect others. One was expected to wear them, and it was considered extremely selfish not to.”

In the US, we have had an aversion to wearing masks as it’s not a part of our normal culture. That aversion stems from a distrust by some of any controls dictated by the government. Some have viewed any mandates as restrictions in personal freedoms. That has been fed by political division going all the way up to the top in our country as Trump has questioned the measure and sides with his supporters who seem to be solidly anti-maskers.

But the data seems to be proving them all wrong.

Efficacy of Masks In Other Countries

Let’s look at that data to see how effective are masks in controlling the spread of the pandemic. The answer is in the data. I’ve been tracking the pandemic since the start, using a fairly elaborate spreadsheet to look at countries, states, and counties. The data goes all the way back to April 1st and could go back to the beginning. But April seems to be a good time to look at it. When looking at the data, I only really look at countries I trust in reporting the data. That includes South Korea, Japan, Australia, Canada, and most of Europe.

So, let’s look at cases in South Korea and Japan. Since the start, both countries have really had a handle on controlling the pandemic to prevent the kind of situation we have in the US today. At the beginning of April, South Korea was seeing new cases averaging around 30 per day. Per capita, that works out to .06 per 100K.

Recently, South Korea is averaging about the same numbers. Granted, they do have spikes such as the last two days, but they address the issue immediately with contact tracing and isolation and bring the numbers back down. Since April, South Korea’s numbers have risen only a little under 5,000. That’s 9.96 people per 100K.

Japan is similar with 7-day average new cases of .91 per 100K now and death increases of .01 per 100K. Germany is probably the best country to look at the effectiveness of masks. Before Germany implemented a mandatory mask mandate towards the end of April, the 7-day new case average on April 19th was 2,475.71. 3 weeks later, that number dropped to 887.86. Today, Germany’s number is 1,085 as the country has been reopening its economy, but still far below the numbers in April.

Efficacy in the US

While these numbers clearly show that masks have worked in other countries, what about the US? While there is not a lot of early data on mask mandates as the nation fought such efforts, recent mandates probably provide the best evidence of how they work. All of these numbers are as of 8/15 when the blog entry was written.

Starting with Texas, which put a mask mandate in place on 7/3 and it took almost 3 weeks for new cases to start dropping. Texas’ 7-day new case average peaked on 7/20 at 10,572. After that, the new cases have been dropping and now stand at 6,910, a drop of 3,662 cases.

AR was late to the game, not putting its mask mandate in place until 7/20. The 7-day new average case rose to 857 on 7/29, then started dropping and now stands at 622, a drop of 235 cases, the majority being in the past week. That showed the flattening of the curve, then the progressive drop.

AL, one of the worst hot spots in the nation, put their mask mandate in place on 7/16. The 7-day new case average peaked at 1,907 on 7/20, then started a slow, but progressive drop to 1,114, a difference of 793 cases per day. Colorado’s 7-day new case average was rising when it put a mandate in place on 7/17, with a peak of 608 on 7/28. At that point, the numbers started dropping and have been dropping since. The 7-day average is now at 378, dropping 230 cases per day. Their 7-day new cases per 100K is now at 6.56.

States that have not put a mask mandate in place include OK, FL, AZ, and TN. Those states have not seen drops in new cases, instead showing a continued, gradual climb in cases.

A recent Texas A&M study looked at mask mandates and their effectiveness. “Our analysis reveals that the difference with and without mandated face covering represents the determinant in shaping the trends of the pandemic worldwide. We conclude that wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission, and this inexpensive practice, in conjunction with extensive testing, quarantine, and contact tracking, poses the most probable fighting opportunity to stop the COVID-19 pandemic, prior to the development of a vaccine.”

I think this provides a good collection of information regarding masks and their effectiveness in this pandemic. We all want this pandemic to subside and our country’s economy to get back on track. To make this happen, we all need to wear masks when in public.

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