In the featured video data scientist Jeremy Howard explains why wearing masks could be a key strategy to reduce the spread of novel coronavirus 2019 (COVID-19), stop lockdowns, get the economy back on track and restore society back to normalcy. Howard, founder of, a research institute dedicated to make Deep Learning more accessible spent eight years in management consulting at McKinsey & Company before that.

In the Czech Republic, wearing masks in public has been required for the whole country since March 18, 2020. Yet, in the U.S., health officials continue to advise the public against it. February 29, 2020, as COVID-19 cases accelerated, the U.S. Surgeon General Dr. Jerome Adams tweeted a message stating, “Seriously people — STOP BUYING MASKS!”

Adams went on to say that masks are not effective in preventing the general public from catching , “but if health care providers can’t get them to care for patients, it puts them and communities at risk!” — statements that blatantly contradict one another. It’s a common refrain that’s been echoed by health officials across the U.S. — masks aren’t effective, except for health care workers.

But as Howard explains in the video above, in countries that have implemented widespread use of masks in public, COVID-19 cases have remained under control. Further, masks can be made inexpensively at home, which means you’re not “stealing” a mask from a health care worker by wearing one in public.

Even some hospitals are asking for donations of medical supplies including homemade masks. If such masks aren’t helpful in reducing transmission of viruses like COVID-19, then why ask for them? The answer is that they are effective — as evidenced by a sizable number of studies.

In the Czech Republic, a grassroots campaign started by a social media influencer led to the widespread use of masks in public — a move that’s saving lives — and the hope is that similar campaigns will spread in the U.S., the U.K. and other countries around the world where wearing masks in public is still stigmatized.

In Countries With ‘Flat Curves,’ Wearing Masks Is Normal

Howard cites data showing that in countries where mask wearing is “extremely normal,” such as South Korea, Japan, Singapore and Hong Kong, they have managed to flatten the curve of COVID-19 cases, keeping them from spiking. Taiwan is missing from the list, as they had so few cases that they weren’t included in the graph.

What happened in Taiwan to keep their cases so limited? Howard notes that they are making up to 10 million masks a day. In an editorial for The New York Times, Zeynep Tufekci, a professor of information science at the University of North Carolina, wrote:

“[P]laces like Hong Kong and Taiwan that jumped to action early with social distancing and universal mask wearing have the pandemic under much greater control, despite having significant travel from mainland China.

Hong Kong health officials credit universal mask wearing as part of the solution and recommend universal mask wearing. In fact, Taiwan responded to the coronavirus by immediately ramping up mask production.”

Even during the 1918 influenza pandemic, if you look at photographs of Americans you’ll see they’re usually wearing masks — something that was ordered by public health officials under penalty of fine or imprisonment. While it’s true that health care workers absolutely need masks, the public, too, can benefit greatly from their widespread usage.

Masks and Hand-Washing Cut Virus Transmission by 75%

In 2012, researchers from the University of Michigan noted a need to establish the efficacy of nonpharmaceutical measures for mitigating pandemics, in this case, influenza. They studied whether the use of face masks and hand hygiene reduced rates of influenza and influenza-like illness (ILI) in 1,178 students living in university residence halls.

The students were assigned to one of three groups: face mask and hand hygiene, face mask only or control group during the study. During weeks three to six of the study, a 75% reduction in influenza-like illness was noted among the students using hand hygiene and wearing masks in residence halls.

“Face masks and hand hygiene combined may reduce the rate of ILI and confirmed influenza in community settings,” the researchers concluded, adding, “These nonpharmaceutical measures should be recommended in crowded settings at the start of an influenza pandemic.”

The study used “standard medical procedure masks with ear loops,” which would likely be comparable to surgical masks. These are loose-fitting pieces of cloth designed to protect you from droplets, which are released when someone coughs or (sometimes) when they talk.

While the specifics of how COVID-19 is spread are still being investigated, according to the U.S. Centers for Disease Control and Prevention, the virus is thought to spread mainly from person-to-person contact, including through respiratory droplets that are produced when an infected person coughs or sneezes.

“These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs,” the CDC states. N95 respirators offer an even higher level of protection, as they’re designed with a full seal intended to protect against airborne or aerosolized pathogens.

As noted by Howard, N95 respirators should be reserved for health care workers performing a limited number of procedures that may expose them to aerosolized pathogens, while surgical masks offer sufficient protection even for most hospital workers — and certainly for the public.

Even Homemade Masks Are Effective

Even wearing homemade masks can offer protection, and as they can be made from materials that are readily available, they shouldn’t carry the stigma that you’re taking a mask away from a health care worker in need. Researchers with Cambridge University tested common household materials for their effectiveness as masks by exposing them to different sized particles.

Surgical masks were most effective, but all of the materials offered some protection even against very small bacteriophages that are even smaller than coronavirus. Surgical masks were 89% effective against 0.02-micron bacteriophage particles, while other materials were rated as follows:

Vacuum cleaner bag — 86%

Dish towel — 73%

Cotton blend T-shirt — 70%

Antimicrobial pillowcase — 68%

Linen — 62%

Pillowcase — 57%

Silk — 54%

100% cotton T-shirt — 51%

Scarf — 49%

The study, which was published in the journal Disaster Medicine and Public Health Preparedness, concluded that even homemade masks are better than no protection at all. Researchers explained:

“The median-fit factor of the homemade masks was one-half that of the surgical masks. Both masks significantly reduced the number of microorganisms expelled by volunteers, although the surgical mask was 3 times more effective in blocking transmission than the homemade mask …

Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection.”

Indeed, Howard also cited virologist Peter Kolchinsky, who tweeted that the public should know that dose matters with COVID-19 exposure. “Masks can help anyone,” he wrote, “reducing amount of virus released (even by breathing) or taken in,” adding that your immune system is more effective if the infection starts with a low dose.

Similarly, a 2008 study published in PLOS One also confirmed that homemade masks are useful. Researchers compared personal respirators, surgical masks and homemade masks worn during a variety of activities and found, “Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence.”

Yet another study from 2004 found that the use of masks was strongly protective against severe acute respiratory syndrome (SARS) in Beijing. Those who always wore a mask when going out had a 70% reduction in risk compared with those who never wore a mask.

Social Media Campaign Makes Mask Wearing ‘Normal’

In the Czech Republic, mask wearing is now seen as a pro-social, selfless act — a measure of kindness for your fellow humans, as wearing a mask not only protects you from others but also protects others from you. According to the CDC, people may spread COVID-19 before they show symptoms.

Asymptomatic transmission of COVID-19 in the U.S. has been downplayed by health officials, but some experts have suggested it could be causing more cases than is currently realized. As such, wearing a mask early on, even if you’re not sick, is important to protect yourself and others.

The Czech Republic mask movement was kicked off by social media influencer Petr Ludwig, who made a video about the importance of wearing masks. Hospitals also reached out on social media asking for homemade masks to fill in gaps of mask shortages, and people responded by not only making masks for health care workers but also for the public.

“Mask trees” emerged, on which people would hang homemade masks in public places where anyone in need could pick one up. They were made with bright colors and patterns, distinguishing them from the surgical masks being prioritized to health care workers. Meanwhile, social media and celebrities got involved, urging people to share the information, take a selfie wearing a mask and use the hashtag #masks4all.

The movement quickly spread, and in the Czech Republic the motto for wearing masks centers on kindness: “Your mask protects me, my mask protects you.” Now, if you’re not wearing a mask in public, you’re considered to be antisocial and putting others at risk — a sharp contrast to the U.S., where mask wearing is still far from commonplace.

Signs Masks Are Going Mainstream

Still, there are signs that this may be changing. In an opinion piece for The New York Times, columnist Farhad Manjoo wrote, “It’s time to make your own face mask,” and suggested wearing one not only in a pinch but as you go about your daily life.  Please go to The New York Times March 31, 2020, article for more resources on how to make your own masks.

Interestingly, yesterday’s NY Times writes that President Trump has finally capitulated on this issue and announced that the Centers for Disease Control and Prevention (CDC) was urging all Americans to wear a face mask when they leave home.

“Say you need to run to the supermarket in an area where there are lots of infections, or you share an apartment with some yahoos who just came back from spring break,” Anna Davis, a researcher at the University, told the Times. Those would be good times to wear a homemade mask, she suggests. Really, any time you go out in public during a pandemic, you and others may benefit from wearing one.

CNN also highlighted the issue, stating that in the coming weeks, more governments may begin advising the public to wear face masks to protect against COVID-19. Speaking with CNN, Ivan Hung, an infectious diseases specialist at the Hong Kong University School of Medicine, explained:

“If you look at the data in Hong Kong, wearing a mask is probably the most important thing in terms of infection control. And it not only brings down the cases of coronaviruses, it also brings down the influenza. In fact, this is now the influenza season, and we hardly see any influenza cases. And that is because the masks actually protected not only against coronaviruses but also against the influenza viruses as well.”

How to Make a Homemade Mask

While the official CDC guidelines still do not include wearing masks for the general public to protect against COVID-19, The Washington Post reported that, as of March 30, 2020, the CDC was considering changing this and advising people to cover their faces when in public using do-it-yourself cloth coverings.

“It’s likely only a matter of time before other mask holdouts, most prominently the World Health Organization, follow suit,” CNN added. If you live in the U.S., you do not need to wait for an official announcement, however.

Follow the trends that have already been proven effective in other countries that have effectively “flattened the curve” of COVID-19 by including masks as part of their general precautions. While N95 respirators and surgical masks should be reserved for those on the front lines, it absolutely makes sense to make your own and use it whenever you’re in public, even if you’re not sick.

The video above shows you how to make a DIY face mask. You can reuse the mask but be sure to clean it regularly by placing it in an oven at 70 degrees C (160 degrees F) for 30 to 60 minutes or expose both sides to an ultraviolet (UV) sterilizer. There are many other videos you can also find online that provide mask making instructions if you want more alternatives, including no-sew options or making a mask out of a T-shirt.

In order to quickly test if your mask is working, Howard suggests going into a room with a smelly odor — if you smell it significantly less when you have your mask on, it’s likely working. According to Howard, every country that has controlled COVID-19 and isn’t in a lockdown has done all of these things:

  1. Rigorous testing regardless of symptoms
  2. Rigorous contact tracing
  3. Quarantining infected persons
  4. Masks for all

In the U.S., the use of surgical masks by the public has been stigmatized due to shortages of personal protective equipment for health care workers. However, wearing homemade masks is a step that virtually everyone can take to protect not only themselves but also the communities around them, especially when used in conjunction with other infection control measures, like hand-washing and healthy diet.


This content was originally published here.