In a media briefing on Mar. 30, 2020, World Health Organization (WHO) officials confirmed that facial masks for the prevention of COVID-19 should be worn by those who are sick or in close contact with those infected, and are not recommended for healthy members of the general population.1 A day later, U.S. Vice President Mike Pence reassured Americans that, “The average American does not need to go out and buy a mask.” U.S. Surgeon General Jerome Adams, MD told Fox News the same day that masks were “not effective” to the general public and tweeted the admonition, “Seriously people-STOP BUYING MASKS!” Despite this guidance, masks and other supplies started to fly off the shelves as Americans stocked up due to fears of an outbreak.2
Conflicting Messages Sow Confusion
Then, on Apr. 3, 2020, the Centers for Disease Control and Prevention (CDC) did an about-face and recommended that everyone use a simple cloth face covering when entering public spaces. Public health officials explained that the face masking policy reversal reflected new concerns that the novel coronavirus was being spread by healthy but infected people who had no symptoms.
The CDC’s new face masking recommendation did not give many details about what kind of face coverings should be used beyond: “cloth face coverings fashioned from household items or made at home from common materials at low cost can be used as an additional, voluntary public health measure.”3
After announcing the new recommendation, President Trump appeared to weaken the recommendations by stating, “This is voluntary. I don’t think I’m going to be doing it.” Dr. Adams admitted that the CDC’s guidelines on face masks have “been confusing” for Americans and he posted a 45-second do-it-yourself mask tutorial the next day.4
To further confuse the situation, the World Health Organization (WHO) released new guidance three days later on Apr. 6 saying that healthy people do not need to wear face masks, and that masks should be reserved for the sick, their caretakers, and healthcare workers. The WHO said there’s some evidence that caretakers of infected people can protect their health by wearing masks but warned:
There is currently no evidence that wearing a mask (whether medical or other types) by healthy persons in the wider community setting, including universal community masking, can prevent them from infection with respiratory viruses, including COVID-19.5
The WHO went on to say that community masking could lead to a “false sense of security” and cause people to ignore other evidence-based measures like hand washing and self-isolation.5
Efficacy of Face Mask Use Unclear
Lisa Brosseau, MD, an expert on respiratory protection and infectious diseases, explains:
When we talk, breathe, cough, or sneeze, we’re producing particles. Some of those particles may be droplets and others may be aerosolized. If you’re infected with a virus, it’s very possible virus will be inside the particles you produce…The size and concentration of these particles will differ depending on if they were produced by a cough or an exhaled breath, but the underlying principle is the same. Large particles will fall to the floor relatively quickly; small particles will travel further.6
Small particles don’t necessarily have a smaller “viral load” according to Dr. Brosseau, who hypothesizes that smaller particles are generated from the deeper part of the lungs where there’s more infection. She maintains that those smaller particles can travel farther and are more likely to slip through protective masks.6
For this reason, Dr. Brosseau disagrees with the CDC’s new guidance for face masking. She said wearing a face mask gives people a false sense of security:
If an infected person wearing a cloth mask coughs, there’s some possibility the mask could block the lateral projection of large particles But it’s not going to do much of anything for those smaller particles. I don’t think it should be a blanket recommendation. It gives people a false sense of security and encourages them to stop isolating, which is really the only thing that’s going to work.6
George Rutherford, MD, an epidemiologist at the University of California-San Francisco’s School of Medicine agrees that social distancing is essential and that cloth masks don’t provide the same protection as someone wearing a perfectly fitting N95 mask. But, he argues, “Don’t let the perfect be the enemy of the good.”6
The CDC reports that recent studies show a significant portion of individuals with coronavirus are asymptomatic. Even those who eventually develop symptoms are thought to transmit the virus to others through coughing, sneezing or speaking before they show symptoms. Therefore, they say that a cloth face covering in public settings where physical distancing is difficult to maintain is meant to protect other people in case an individual is infected.7
How Long Does COVID-19 Remain on Surfaces or in the Air?
A recent study8 found that the SARS-CoV-2 (the virus believed to cause COVID-19) could remain on common surfaces for up to 72 hours or in the air as an aerosol for up to 3 hours. Linsey Marr, PhD, an expert on aerosol transmission of viruses at Virginia Tech University told The New York Times in March 2020 that an aerosol released at a height of about 6 feet should fall to the ground after 34 minutes. The amount of the virus that lingers in the air as an aerosol is also likely too small to infect someone, she said:
It sounds scary. But unless you’re close to someone, the amount you’ve been exposed to is very low.9
The WHO has cast doubt on study findings suggesting that SARS-CoV-2 is transmissible as an airborne pathogen, arguing that the experiment used “a high-powered machine that does not reflect normal human cough conditions” and therefore “these initial findings need to be interpreted carefully.” However, Donald Milton, MD, a professor and infectious disease aerobiologist at the University of Maryland, counters that, “Epidemiologists cannot tell the difference between droplet transmission and short-range aerosol transmission,” so because of the uncertainty about COVID-19, WHO should “employ the precautionary principle to recommend airborne precautions.”10
Shortages of Masks Tied to U.S. Exports in Early 2020
The N95 medical-grade masks, which are designed to fit tightly to the face, appear to be effective at filtering viruses for workers in health care settings. However, hospitals continue to report a shortage of masks.
On Feb. 25, 2020, Health and Human Services Secretary Alex Azar said that there were “30 million N95 respirators in the national strategic stockpile” and that 270 million more face masks were needed for health-care workers.11 Since then, the CDC has continued to warn that N95 and surgical masks are critical supplies that must be reserved for healthcare workers and other medical first responders.
An investigative report by USA Today published on Apr. 2, 2020, revealed one big reason for the shortage: millions of surgical masks were exported from the U.S. to China in January and February of 2020:
U.S. exports of surgical masks, ventilators and other personal protective gear to China skyrocketed in January and February, when the coronavirus was wreaking havoc in the country where it began and as U.S. intelligence agencies warned it would soon spread. American companies sold more than $17.5 million worth of face masks, more than $13.6 million in surgical garments and more than $27.2 million in ventilators to China during the first two months of the year, far exceeding that of any other similar period in the past decade, according to the most recent foreign trade data available from the U.S. Census Bureau.12
Does Face Masking Work for the Average Person?
Some experts have said there is little need for the average person to wear a face mask to prevent getting infected with or transmitting COVID-19. “In the research that’s been done, we don’t see any benefit at the community level for wearing the mask,” said Amanda McClelland, MPH., a senior vice president at Vital Strategies, a public health organization that focuses on global health threats.13
But studies of dorms and other high-density settings like households do show some efficacy for masks, according to Raina MacIntyre, PhD, professor of global biosecurity at the University of New South Wales Sydney in Australia. A 2010 study14 found that the combination of mask use, providing alcohol-based hand sanitizer, and education about hand and cough hygiene reduced the prevalence of flulike illness inside a college dorm to a greater degree than only hand and cough hygiene education. “If they work in high-transmission settings, they should also work in low-intensity settings,” Dr. MacIntyre said.15
A 2011, Cochrane reviewed 67 studies16 and found that face mask use, hand washing and isolating sick people, especially when used together, can be effective in containing transmission of viral infections in epidemics.
“The argument is that since anyone can be infected without knowing it and spread the infection, that everyone should wear masks,” said University of Maryland professor Donald Milton, PhD. He added, “In the U.S., where we are not prepared to test rapidly and aggressively trace and quarantine all contacts, surgical masks could be helpful.”
Are Homemade Masks Effective?
Evidence of the effectiveness of homemade masks is mixed. A study published in the British Medical Journal in 201517 found that healthcare workers using cloth masks were more likely to be infected with respiratory diseases than those who used disposable surgical masks, even when workers washed them at the end of each shift. Two laboratory studies18 19 demonstrated that masks made of household materials such as T-shirt scraps, tea cloths, or vacuum bags, aren’t as effective at blocking particles of virus in droplets and aerosols as surgical masks.
Still, the homemade masks did provide some protection—especially those made of vacuum bags, tea towels, and blended cotton fabric. A 2006 study20 of homemade T-shirt masks found they could provide a “measurable level of protection” from a challenge aerosol.
While some experts say wearing a homemade or purchased mask may help you remember not to touch your face, others note that they can be uncomfortable and require frequent adjustment. Individuals are also likely to take a mask off to eat or drink, then put it back on afterward. That defeats the purpose, said McClelland. She said:
People contaminate themselves more by touching the mask and taking it on and off their face.3
Deborah Birx, MD, coronavirus response coordinator for the White House coronavirus task force, notes that mask wearers must still continue other safety measures, including social distancing.
“Because homemade ones are not even as effective at filtering out virus as commercial surgical masks, which are not great, people should be aware that these are not protective and should not do anything you would not do without one of them on,” Dr. Milton said.
Proper Face Mask Use is Key Says Surgeon General
Dr. Adams says people should wash their hands before donning a mask and avoid touching their faces while wearing one. He also advised people not to touch their eyes, nose, and mouth while removing the covering, place the covering where it won’t be touched by anyone else in the house and where it won’t contaminate other surfaces, and wash hands right away.
Masking Requirements by State Governments Vary
The CDC recommends wearing cloth face coverings “in public settings where other social distancing measures are difficult to maintain, especially in areas of significant community-based transmission.”21 Although there is no national mandate by the federal government, several states and municipalities in the U.S. now require everyone to wear masks.
State government officials in New York joined Maryland and New Jersey in ordering residents to wear masks in certain situations. Los Angeles officials are requiring shoppers and workers to wear face coverings during “essential shopping,” and have authorized employers to refuse any employee not wearing a face covering entry to a work space.22
Universal Face Masking to Prevent Stigma and Discrimination?
Globally, face mask recommendations vary across countries. Use of masks in community settings appears to increase substantially once local epidemics begin. This increase in use of face masks by the general public contributes to the supply shortage of face masks in some countries, sending prices soaring and risking personal protective equipment (PPE) supply problems for frontline health care workers.23
There are societal and cultural paradigms around the wearing of masks to prevent transmission of infections. While face masks are commonly used as a preventive public health practice in many Asian countries, in European and North American countries it is something people only consider doing when they are sick.
Some social scientists and public health professionals believe that universal masking by the sick and healthy alike prevents identification, stigmatization and discrimination against individuals who wear masks because, if everyone wears a face mask, there are no perceived differences between the healthy and the sick.24
1 Lacina L. Should you wear a face mask? WHO officials weigh in at today’s COVID-19 briefing. World Economic Forum Mar. 30, 2020.
2 Perrett C. The US Surgeon General once warned against wearing face masks for the coronavirus but the CDC now recommends it. Business Insider Mar. 2, 2020.
3 Dwyer C, Aubrey A. CDC Now Recommends Americans Consider Wearing Cloth Face Coverings In Public. NPR Apr. 3, 2020.
4 Centers for Disease Control and Prevention. How to Make Your Own Face Covering. Apr. 3, 2020.
5 Naftulin, J. WHO says there is no need for healthy people to wear face masks, days after the CDC told all Americans to cover their faces. Business Insider France Apr. 7, 2020.
6 MacBride K. Your Mask May Not Be Enough if COVID-19 Is in the Air. The Daily Beast Apr. 11, 2020.
7 CDC. Coronavirus Disease 2019: Recommendations for Cloth Face Covers. Apr. 3, 2020.
8 van Doremalen N, Bushmaker T, et. al. Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. New England Journal of Medicine Apr. 16, 2020; 382: 1564-1567.
9 Mandavilli A. How Long Will Coronavirus Live on Surfaces or in the Air Around You? The New York Times Apr. 1, 2020.
10 Dunleavy, J. World Health Organization insists coronavirus not an airborne disease as experts raise possibility. Washington Examiner Mar. 30, 2020.
11 Fink J. America has 30 Million Masks, Needs 300 Million for Health Care Workers Fighting Coronavirus, HHS Secretary Says. Newsweek Feb. 25, 2020.
12 Shang D, Mansfield E, Pulver DV. U.S. exported millions in masks and ventilators ahead of the coronavirus crisis. USA Today Apr. 2, 2020.
13 Roberts C. What to Know Now About Masks and Coronavirus. Consumer Reports Apr. 3, 2020.
14 Aiello A, Murray GF, et. al. Mask use, hand hygiene, and seasonal influenza-like illness among young adults: A randomized intervention trial. The Journal of Infectious Diseases Feb. 15, 2010; 201(4): 491-498.
15 See Footnote 13.
16 Jefferson T, Del Mar CB, et. al. Physical interventions to interrupt or reduce the spread of respiratory viruses. Cochrane Database of Systematic Reviews July 6, 2011; 7.
17 Feng S, Shen C, et. al. Rational use of face masks in the COVID-19 pandemic. The Lancet Respiratory Medicine Mar. 20, 2020.
18 Davies A, Thompson K, et. al. Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic? Disaster Medicine and Public Health Preparedness August 2013; 7(4): 413-418.
19 Van der Sande M, Teunis P, Sabel R. Professional and Home-Made Face Masks Reduce Exposure to Respiratory Infections among the General Population. PLoS One July 9, 2008; 3(7): e2618.
20 Data VM, Hostler D, Hahn M. Simple Respiratory Mask. Emerging Infectious Diseases June 2006; 12(6): 1033-1034.
21 CDC. Coronavirus Disease 2019: Recommendations for Cloth Face Covers. Apr. 3, 2020.
22 Stanglin D. Where are you required to wear a face mask? More and more states, cities and towns making it a rule. USA Today Apr. 16, 2020 (Updated Apr 16, 2020).
23 Feng S, Shen C, et. al. Rational use of face masks in the COVID-19 pandemic. The Lancet Respiratory Medicine Mar. 20, 2020.