Cloth Masks Do Protect the Wearer - Breathing in Less Coronavirus Means You Get Less Sick
By Monica Gandhi
Masks slow the spread of SARS-CoV-2 by reducing how much infected people spray the virus into the environment around them when they cough or talk. Evidence from laboratory experiments, hospitals and whole countries show that masks work, and the Centers for Disease Control and Prevention recommends face coverings for the U.S. public. With all this evidence, mask wearing has become the norm in many places.
I am an infectious disease doctor and a professor of medicine at the University of California, San Francisco. As governments and workplaces began to recommend or mandate mask wearing, my colleagues and I noticed an interesting trend. In places where most people wore masks, those who did get infected seemed dramatically less likely to get severely ill compared to places with less mask-wearing.
It seems people get less sick if they wear a mask.
When you wear a mask – even a cloth mask – you typically are exposed to a lower dose of the coronavirus than if you didn't. Both recent experiments in animal models using coronavirus and nearly a hundred years of viral research show that lower viral doses usually means less severe disease.
No mask is perfect, and wearing one might not prevent you from getting infected. But it might be the difference between a case of COVID-19 that sends you to the hospital and a case so mild you don't even realize you're infected.
Exposure Dose Determines Severity of Disease
When you breathe in a respiratory virus, it immediately begins hijacking any cells it lands near to turn them into virus production machines. The immune system tries to stop this process to halt the spread of the virus.
The amount of virus that you're exposed to – called the viral inoculum, or dose – has a lot to do with how sick you get. If the exposure dose is very high, the immune response can become overwhelmed. Between the virus taking over huge numbers of cells and the immune system's drastic efforts to contain the infection, a lot of damage is done to the body and a person can become very sick.
On the other hand, if the initial dose of the virus is small, the immune system is able to contain the virus with less drastic measures. If this happens, the person experiences fewer symptoms, if any.
This concept of viral dose being related to disease severity has been around for almost a century. Many animal studies have shown that the higher the dose of a virus you give an animal, the more sick it becomes. In 2015, researchers tested this concept in human volunteers using a nonlethal flu virus and found the same result. The higher the flu virus dose given to the volunteers, the sicker they became.
In July, researchers published a paper showing that viral dose was related to disease severity in hamsters exposed to the coronavirus. Hamsters who were given a higher viral dose got more sick than hamsters given a lower dose.
Based on this body of research, it seems very likely that if you are exposed to SARS-CoV-2, the lower the dose, the less sick you will get.
So what can a person do to lower the exposure dose?
Masks Reduce Viral Dose
Most infectious disease researchers and epidemiologists believe that the coronavirus is mostly spread by airborne droplets and, to a lesser extent, tiny aerosols. Research shows that both cloth and surgical masks can block the majority of particles that could contain SARS-CoV-2. While no mask is perfect, the goal is not to block all of the virus, but simply reduce the amount that you might inhale. Almost any mask will successfully block some amount.
Laboratory experiments have shown that good cloth masks and surgical masks could block at least 80% of viral particles from entering your nose and mouth. Those particles and other contaminants will get trapped in the fibers of the mask, so the CDC recommends washing your cloth mask after each use if possible.
The final piece of experimental evidence showing that masks reduce viral dose comes from another hamster experiment. Hamsters were divided into an unmasked group and a masked group by placing surgical mask material over the pipes that brought air into the cages of the masked group. Hamsters infected with the coronavirus were placed in cages next to the masked and unmasked hamsters, and air was pumped from the infected cages into the cages with uninfected hamsters.
As expected, the masked hamsters were less likely to get infected with COVID-19. But when some of the masked hamsters did get infected, they had more mild disease than the unmasked hamsters.
Masks Increase Rate of Asymptomatic Cases
In July, the CDC estimated that around 40% of people infected with SARS-CoV-2 are asymptomatic, and a number of other studies have confirmed this number.
However, in places where everyone wears masks, the rate of asymptomatic infection seems to be much higher. In an outbreak on an Australian cruise ship called the Greg Mortimer in late March, the passengers were all given surgical masks and the staff were given N95 masks after the first case of COVID-19 was identified. Mask usage was apparently very high, and even though 128 of the 217 passengers and staff eventually tested positive for the coronavirus, 81% of the infected people remained asymptomatic.
Further evidence has come from two more recent outbreaks, the first at a seafood processing plant in Oregon and the second at a chicken processing plant in Arkansas. In both places, the workers were provided masks and required to wear them at all times. In the outbreaks from both plants, nearly 95% of infected people were asymptomatic.
There is no doubt that universal mask wearing slows the spread of the coronavirus. My colleagues and I believe that evidence from laboratory experiments, case studies like the cruise ship and food processing plant outbreaks and long-known biological principles make a strong case that masks protect the wearer too.
The goal of any tool to fight this pandemic is to slow the spread of the virus and save lives. Universal masking will do both.
Monica Gandh is a Professor of Medicine, Division of HIV, Infectious Diseases and Global Medicine at the University of California, San Francisco.
Disclosure statement: Monica Gandhi does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Reposted with permission from The Conversation.
By Jennifer Ann Thomas
For the first time, researchers have developed a model capable of anticipating drought periods in the Amazon up to 18 months in advance. The study was conducted by scientists from the Potsdam Institute for Climate Impact Research (PIK), in Germany, as part of the Tipping Points in the Earth System (TiPES) project, led by physicist Catrin Ciemer and published in the journal Environmental Research Letters.
Average monthly sea surface temperature (in degrees Celsius, red scale) and average continental rainfall in South America (in millimeters/month, blue scale) from 1981 to 2016. Sea surface temperatures and precipitation are generally higher around the equator. On the left, the area where El Niño – Southern Oscillation (ENSO) occurs; dotted lines indicate the Intertropical Convergence Zone (ITCZ) in January and July, responsible for transporting heat and humidity from the oceans around the tropics.
- Amazon Rainforest Could be Two Years from Irreversible ›
- Deforestation in Brazilian Amazon Increases for 13th Consecutive ... ›
- Climate Change Could Bring Drought to Amazon, Greater Rain to ... ›
EcoWatch Daily Newsletter
By Sean Fleming
Londoners worrying about air quality can now breathe a little easier, thanks to news from the city's mayor.
- 'Car-Free Zones' Launching in London - EcoWatch ›
- Protesting Against Air Pollution Crisis, Extinction Rebellion Stalls ... ›
- Corporations Don't Have to Pay Pollution Fines During COVID-19 ... ›
- Does Air Pollution Increase Depression and Suicide? - EcoWatch ›
Japanese Prime Minister Yoshihide Suga announced that Japan will become country carbon neutral by 2050, Bloomberg reported.
- Student Climate Protesters Urge Universities to Go Carbon Neutral ... ›
- This Country Is Already Carbon Neutral and Now Plans to Go 100 ... ›
- Climate Action Must Go Deeper Than 'Carbon Neutral' - EcoWatch ›
- Exposed: Chevron's Secretive Drilling Site in the Arctic National ... ›
- Trump Admin Pushes Final Drilling Plan for Arctic National Wildlife ... ›
By Derrick Z. Jackson
Officials at the highest levels are discussing the possibility of caving in on controlling the coronavirus and instead letting it run rampant throughout the United States until we reach "herd immunity," the point where the virus effectively runs out of people to infect. More than 6,200 scientists, health professionals, and research organizations say this is inhumane and have signed a memorandum rejecting herd immunity as a legitimate strategy.
Herd Immunity’s Unacceptable Toll<p>Resumption of normal life in the United States under a herd immunity approach would result in an enormous death toll by all estimates. Former CDC director Tom Frieden <a href="https://www.washingtonpost.com/opinions/tom-frieden-herd-immunity-wrong-solution-coronavirus/2020/10/16/acb4ae8a-0fe6-11eb-8074-0e943a91bf08_story.html" target="_blank">estimates</a> that another 500,000 people would have to die to achieve 60 percent herd immunity. "And that's the best-case scenario," Frieden wrote in a <em>Washington Post</em> op-ed. "The number of deaths to get there could be twice as high."</p><p>Frieden said that is the best-case scenario because no one really knows if the <a href="https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/herd-immunity-and-coronavirus/art-20486808" target="_blank">actual percentage needed</a> to see the virus peter out is to have it <a href="https://thehill.com/opinion/healthcare/521834-covid-19-vaccine-barriers-efficacy-availability-and-acceptability" target="_blank" rel="noopener noreferrer">infect</a> more like <a href="https://www.washingtonpost.com/health/2020/08/31/herd-immunity-covid-19/" target="_blank" rel="noopener noreferrer">65, 70,</a> or even <a href="https://www.vox.com/21451282/herd-immunity-explained-covid-19-pandemic" target="_blank" rel="noopener noreferrer">75 percent</a> of the population. Even if immunity could be miraculously achieved at 50 percent, an estimate <a href="https://www.nature.com/articles/s41577-020-00451-5" target="_blank" rel="noopener noreferrer">published</a> in <em>Nature Reviews Immunology</em> places the range of sacrifice somewhere between 500,000 and 2.1 million deaths.</p><p>That makes it little wonder that Anthony Fauci, the most respected scientist advising the Trump administration on the pandemic, called herd immunity for the coronavirus "total nonsense." Fauci is backed up by the likes of National Institutes of Health Director Francis Collins, who said herd immunity is a "dangerous" and "fringe" component of epidemiology. Ashish Jha, dean of the Brown University School of Health <a href="https://www.bostonglobe.com/2020/10/20/nation/scores-mass-scientists-doctors-sign-open-letter-against-herd-immunity-proposal/?outputType=amp" target="_blank" rel="noopener noreferrer">called</a> herd immunity "junk science."</p><p>The head of the World Health Organization (WHO), Tedros Adhanom Ghebreyesus, <a href="https://www.who.int/dg/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---12-october-2020" target="_blank" rel="noopener noreferrer">said this month</a> that the only acceptable form of "herd immunity" is achieved through vaccination. "Herd immunity is achieved by protecting people from a virus, not by exposing them to it," the secretary general said. "Never in the history of public health has herd immunity been used as a strategy for responding to an outbreak, let alone a pandemic... Allowing a dangerous virus that we don't fully understand to run free is simply unethical. It's not an option."</p>
Herd Immunity Is the National De Facto Strategy<p>Somehow, none of that has culled herd immunity from being considered as a legitimate approach for fighting COVID-19. Rather, the Great Barrington Declaration has much in common with the Trump administration's approach to the coronavirus, which has led to more people dying from COVID-19 in the United States than in any other nation on Earth.</p><p>A de facto herd immunity approach is the only thing that can explain the push by governors of so many states to <a href="https://blog.ucsusa.org/derrick-jackson/the-push-to-relax-covid-19-protections-exposes-age-old-racial-wounds" target="_blank">reopen</a> bars, restaurants, beaches, bowling alleys, and gyms in states even as the virus has raged and case numbers have been increasing. It is the only thing that can explain the federal designation of meatpackers as essential workers and state demands that teachers go back into classrooms despite outbreaks and deaths related to those professions.</p><p>It also explains how so many of the nation's most respected scientific voices have been silenced. Despite the virus's current "uncontrolled spread" in 34 states and Puerto Rico, according to October 21 <a href="https://www.covidexitstrategy.org/" target="_blank" rel="noopener noreferrer">tracking</a> by CovidExistStrategy.org, the White House has pushed aside Fauci, Coronavirus Task Force Coordinator Deborah Birx, Surgeon General Jerome Adams, and Robert Redfield, the head of the Centers for Disease Prevention and Control.</p><p>In their place, the administration has handed the pandemic podium to <a href="https://www.washingtonpost.com/politics/trumps-den-of-dissent-inside-the-white-house-task-force-as-coronavirus-surges/2020/10/19/7ff8ee6a-0a6e-11eb-859b-f9c27abe638d_story.html?utm_campaign=wp_to_your_health&utm_medium=email&utm_source=newsletter&wpisrc=nl_tyh&wpmk=1&pwapi_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJjb29raWVuYW1lIjoid3BfY3J0aWQiLCJpc3MiOiJDYXJ0YSIsImNvb2tpZXZhbHVlIjoiNWE1ZDQ3N2M5YmJjMGYyNmNiMTViMmI0IiwidGFnIjoiNWY4ZGZhZmQ5ZDJmZGEwZWZiNGViMzQyIiwidXJsIjoiaHR0cHM6Ly93d3cud2FzaGluZ3RvbnBvc3QuY29tL3BvbGl0aWNzL3RydW1wcy1kZW4tb2YtZGlzc2VudC1pbnNpZGUtdGhlLXdoaXRlLWhvdXNlLXRhc2stZm9yY2UtYXMtY29yb25hdmlydXMtc3VyZ2VzLzIwMjAvMTAvMTkvN2ZmOGVlNmEtMGE2ZS0xMWViLTg1OWItZjljMjdhYmU2MzhkX3N0b3J5Lmh0bWw_dXRtX2NhbXBhaWduPXdwX3RvX3lvdXJfaGVhbHRoJnV0bV9tZWRpdW09ZW1haWwmdXRtX3NvdXJjZT1uZXdzbGV0dGVyJndwaXNyYz1ubF90eWgmd3Btaz0xIn0.MyoXrwQD-PwWqdbb70_JfrI_fxHO0be_O_tpTTMXBgE" target="_blank" rel="noopener noreferrer">Scott Atlas</a>, a radiologist and conservative pundit with <a href="https://blog.ucsusa.org/derrick-jackson/public-wants-science-based-policies-for-covid-19" target="_blank" rel="noopener noreferrer">no background</a> in infectious disease science or epidemiology in measuring disease prevalence. Inhumanely ignoring the more than half of U.S. adults having a pre-existing condition that could compromise them for COVID-19, he blithely praises herd immunity, <a href="https://blog.ucsusa.org/derrick-jackson/public-wants-science-based-policies-for-covid-19" target="_blank" rel="noopener noreferrer">saying,</a> "We can allow a lot of people to get infected. Those who are not at risk to die or have a serious hospital-requiring illness, we should be fine with letting them get infected."</p><p>He <a href="https://thehill.com/homenews/administration/521688-birx-confronted-pence-about-atlas" target="_blank" rel="noopener noreferrer">pooh-poohs</a> expanded testing, saying, "you are destroying the workforce." Twitter recently took down one of Atlas's tweets for falsely claiming, "Masks work? NO" and then lying that the WHO says widespread mask use is "not supported." The first sentence of the WHO's <a href="https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/when-and-how-to-use-masks" target="_blank" rel="noopener noreferrer">webpage</a> on masks says, "Masks are a key measure to suppress the spread of COVID-19 and save lives."</p><p>Atlas denies that the White House has a "wide-open strategy of achieving herd immunity." But there's little doubt that the White House is wide open to the idea. Last week, Atlas <a href="https://www.foxnews.com/transcript/trump-adviser-calls-nbc-town-hall-brazen-display-of-media-duplicity" target="_blank" rel="noopener noreferrer">appeared</a> on Fox News <a href="https://www.wsj.com/articles/white-house-touts-document-calling-for-herd-immunity-approach-to-covid-19-crisis-11603051550" target="_blank" rel="noopener noreferrer">to say</a> the thrust of the Great Barrington Declaration "is exactly aligned with the president." That was seconded by a senior administration official who <a href="https://www.washingtonpost.com/health/covid-herd-immunity/2020/10/10/3910251c-0a60-11eb-859b-f9c27abe638d_story.html" target="_blank" rel="noopener noreferrer">told reporters</a> in a conference call that the Great Barrington Declaration "is endorsing what the president's policy has been for months."</p><p>The freezing out of scientists on the Coronavirus Task Force reached deep space levels this week (a metaphoric minus 455 degrees Fahrenheit), with multiple buckets of ice dumped on Fauci. Atlas diminished Fauci as "just one person" on the force, offering only a "limited approach." President Trump called Fauci a "disaster," <a href="https://www.washingtonpost.com/politics/trump-fauci-campaign-biden/2020/10/19/30b2fe58-1226-11eb-82af-864652063d61_story.html" target="_blank" rel="noopener noreferrer">claiming,</a> "People are tired of hearing Fauci and these idiots, all these idiots who got it wrong."</p>
Many Thousands of Lives Can Still Be Saved<p>Atlas's malpractice already merits his dismissal. He should be forced to step down because his disregard for science will surely lead to incalculable disaster if a herd immunity approach becomes official government policy. Calls for his ouster have already begun even from inside the task force. <a href="https://www.washingtonpost.com/politics/trumps-den-of-dissent-inside-the-white-house-task-force-as-coronavirus-surges/2020/10/19/7ff8ee6a-0a6e-11eb-859b-f9c27abe638d_story.html" target="_blank">According</a> to the <em>Washington Post</em>, Birx went to Vice President Mike Pence to suggest removing Atlas. All Pence reportedly did was ask Birx and Atlas to work out their problems on their own.</p><p>There is no time left for such discord within the task force and for discordant messages to come from the White House on how people should protect themselves from COVID-19. The thousands of scientists and public health professionals who signed the John Snow Memorandum say "it is critical to act decisively and urgently," to launch a "robust" response on the level of New Zealand, Vietnam, or Japan—all of which have shown success in containing the virus and keeping the numbers of cases and deaths relatively low.</p><p>The approach that has been proven effective starts with face coverings and social distancing and reducing the temptation we all will feel during the oncoming winter holidays to have extended family gatherings. Researchers from MIT and the Vancouver School of Economics <a href="https://www.medrxiv.org/content/10.1101/2020.05.27.20115139v6.full.pdf" target="_blank">estimate</a> in a working paper that, if the United States had established a national mask mandate in mid-March, between 19,000 and 47,000 lives could have been saved by the end of May. Now that the nation's death toll approaches a quarter million lives lost, and is <a href="https://covid19.healthdata.org/united-states-of-america?view=total-deaths&tab=trend" target="_blank" rel="noopener noreferrer">projected</a> to reach nearly 400,000 by February 1, according to the Institutes for Health Metrics and Evaluation at the University of Washington, the institute estimates we could avoid 74,000 new deaths with universal mask use.</p><p>Importantly, masks protect others, including the most vulnerable among us. This week, the <em>Washington Post</em> reported how coronavirus outbreaks among college students partying in unmasked packs in LaCrosse, Wisconsin was found to have <a href="https://www.washingtonpost.com/health/2020/10/21/la-crosse-wisconsin-covid-outbreak-nursing-home-deaths/?utm_campaign=wp_to_your_health&utm_medium=email&utm_source=newsletter&wpisrc=nl_tyh&wpmk=1&pwapi_token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJjb29raWVuYW1lIjoid3BfY3J0aWQiLCJpc3MiOiJDYXJ0YSIsImNvb2tpZXZhbHVlIjoiNWE1ZDQ3N2M5YmJjMGYyNmNiMTViMmI0IiwidGFnIjoiNWY5MWU3YjU5ZDJmZGEwZWZiNTE3OGNmIiwidXJsIjoiaHR0cHM6Ly93d3cud2FzaGluZ3RvbnBvc3QuY29tL2hlYWx0aC8yMDIwLzEwLzIxL2xhLWNyb3NzZS13aXNjb25zaW4tY292aWQtb3V0YnJlYWstbnVyc2luZy1ob21lLWRlYXRocy8_dXRtX2NhbXBhaWduPXdwX3RvX3lvdXJfaGVhbHRoJnV0bV9tZWRpdW09ZW1haWwmdXRtX3NvdXJjZT1uZXdzbGV0dGVyJndwaXNyYz1ubF90eWgmd3Btaz0xIn0.6Ep-AvkJkNqGTE08UsekVlNWR01vYzQe-qg5BPruSQM" target="_blank" rel="noopener noreferrer">led to 19 deaths so far of people over the age of 60</a>. Before that, the city had gone without a single pandemic death in its nursing homes.</p><p>That is on the heels of the wedding in Millinocket, Maine that resulted in an outbreak that <a href="https://bangordailynews.com/2020/09/19/news/eight-deaths-now-tied-to-millinocket-area-wedding-outbreak-including-seven-at-nursing-home/" target="_blank" rel="noopener noreferrer">killed eight elderly people</a>, none of whom attended the event, and the 500,000-person Sturgis, South Dakota motorcycle rally that is <a href="https://www.washingtonpost.com/health/2020/10/17/sturgis-rally-spread/" target="_blank" rel="noopener noreferrer">now tied</a> to the massive coronavirus outbreak in the Upper Midwest and Mountain States. The Germain IZA Institute of Labor Economics estimates that the illness generated from the rally <a href="https://www.iza.org/publications/dp/13670/the-contagion-externality-of-a-superspreading-event-the-sturgis-motorcycle-rally-and-covid-19" target="_blank" rel="noopener noreferrer">will cost</a> the nation $12.2 billion in health care costs.</p><p>Atlas and the proponents of the Great Barrington Declaration have not yet said why this is just fine. That is why they must be unmasked for the charlatans that they are.</p>
- Coronavirus Infections Could Be 13x Higher Than Reported, New ... ›
- How Do You Stay Safe Now That States Are Reopening? - EcoWatch ›
- Shutdowns Stopped 60 Million COVID-19 Infections in the U.S., New ... ›