No one who reads this commentary should take it as advice to avoid wearing a face-covering in public in these days of COVID-19. But neither is it an argument for masking.
True believers in masking can probably stop reading now and click here for a link to Dr. Trisha Greenhalgh’s argument for public masking. She offers solid, reasoned arguments for what you wish to believe.
She brought them to the attention of Carl Heneghan and Tom Jefferson at Oxford University’s Centre for Evidence-Based Medicine (CEBM) after they earlier posted a review of what science can say in reply to the question of “masks on or off.”
“That review was mostly focused on medical masks for healthcare workers but also looked at randomized controlled trials of masks and face coverings for the lay public. Heneghan and Jefferson’s interpretation of that evidence was that there is insufficient evidence to support mask-wearing by members of the public. They also speculated that masks could cause harm,” Greenhalgh later wrote on the CEBM website.
“My own interpretation of the evidence is different. I acknowledge that many scientists find the evidence unconvincing, and I fully agree with Carl and Tom that randomised controlled trial evidence of efficacy is lacking.”
Let us start there with some observations.
World of medicine
One of the first things to recognize in this discussion is that the use of face masks in public is little like the use of face masks in the medical community where people are trained in their use to try to minimize the spread of pathogens.
When those in the medical community expect to be exposed to dangerous viruses, they wear full personal protective equipment (PPE), consisting not only of masks but adding gowns, gloves, goggles, caps and shoe covers.
Most importantly, they are careful when they remove that PPE to avoid cross-contamination of the working environment. After you have been in an room likely to smear your PPE with SARS-CoV-2 viruses – the pathogens that cause COVID-19 – you want to carefully dispose of that PPE so as to avoid contaminating anything else.
No one at this time knows exactly how SARS-CoV-2 spreads, but so-called fomites, objects of any sort on which SARS-CoV-2 viruses land, are one likely source along with respiratory droplets, which have been much discussed, and aerosols, which are basically invisible, free-floating germs.
The medical world recognizes all these forms in which infectious diseases spread and takes steps to halt them all. Those steps – regular changes of PPE, periodic handwashing, proper handing of contaminated PPE – are not so easy in the real world.
Let’s take for example someone headed out on a shopping trip. They wash their hands before leaving the house and take a face covering with them. They put their face covering on at their destination, do their shopping, and then what?
Pull it off? Hang it from the mirror in the car? Throw it on the empty passenger seat? Since most motor vehicles lack sinks and running water, handwashing is out of the question. Do most people carry disinfectant wipes with which to clean up after unmasking?
They should be. The only study of masks and SARS-CoV-2, specifically, found the virus passing through the masks in some way.
“Neither surgical nor cotton masks effectively filtered SARS–CoV-2 during coughs by infected patients. Prior evidence that surgical masks effectively filtered influenza virus informed recommendations that patients with confirmed or suspected COVID-19 should wear face masks to prevent transmission,” Korean doctors reported in peer-reviewed examination in the Annals of Internal Medicine.
The sample size for the study was small, but given that it was a simple examination of the physical filtering capabilities of masks this is somewhat irrelevant. The study answered the simplest question of whether masks will block emissions of SARS-CoV-2, and it appears they won’t.
It didn’t, however, answer the most important question: Will masks reduce the spread of SARS-CoV-2? That question hinges on aerosols and fomites, which present their own questions.
If the mask stops droplets, do the exhalations of infected people forced SARS-CoV-2 out of the droplets and fill the air with SARS-CoV-2 aerosols, and can those aerosols infect others?
If SARS-CoV-2 is accumulating on the masks – “all swabs from the outer mask surfaces of the masks were positive for SARS–CoV-2,” the Korean doctors reported – can people who touch the front of the mask with their hand grab a handful of SARS-CoV-2 to subsequently deposit on anything they touch?
The answer to these questions remains unknown. The U.S. Centers for Disease Control (CDC) caused a bit of an uproar last week when it rewrote its SARS-CoV-2 safety warnings in such a way that some journalists read the new advice to indicate fomites are not a danger.
“Based on data from lab studies on COVID-19 and what we know about similar respiratory diseases, it may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose or possibly their eyes,” it said. “But this isn’t thought to be the main way the virus spreads.”
The keywords there are “isn’t thought to be.” The reality is that science is still in the dark on this one.
“Up until 1987, the Centers for Disease Control and the American Hospital Association focused on patient diagnosis due to the belief that (hospital-acquired) infections were not related to microbial contamination of surfaces,” scientists observed in a peer-reviewed study in the journal of Applied and Environment Microbiology in 2007. “Over the years studies have changed the perspective on viral transmission to include a more complex multifactorial model of disease spread. There is now growing evidence that contaminated fomites or surfaces play a key role in the spread of viral infections.”
Scientists modeling how to prevent the flu in 2012 noted that “previous studies have highlighted the importance of the ‘indirect contact’ route. Uncertainty analysis found that despite the relatively fast inactivation of influenza virus on hands and surfaces, contact transmission remains a viable transmission route, in part due to the vast volumetric majority (99.99 percent) of cough excretions being so large that they settle from the air rapidly. Due to this result, as well as the increasing interest in hand hygiene and decontamination to control a wide range of infectious diseases, we focus here on the indirect contact route.”
An analysis of the SARS-CoV-2 virus published in the New England Journal of Medicine in April found it “viable in aerosols” for at least three hours and calculated the “estimated median half-life of SARS-CoV-2 was approximately 5.6 hours on stainless steel and 6.8 hours on plastic….
“Our results indicate that aerosol and fomite transmission of SARS-CoV-2 is plausible since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days.”
Those damn germs
Though we cannot see what used to be called simply “germs,” microscopic pathogens are everywhere in our world. Over the last 300,000 years or so, the human immune system evolved to deal with them. Humans notably did not – nor did any mammal – develop a respiratory filtering system as a protective measure.
Evolutionary biology settled on respiratory systems that maximize the transfer of air in order to optimize individual supplies of oxygen, an invisible chemical in the air without which we die. An argument can be made that this style of respiratory system is now outdated.
It evolved to support a species required to be constantly active to survive. The oxygen needs of those living what is now called the “sedentary lifestyle” are notably lower than for those engaged in strenuous physical activity although there does appear to remain some value in efficiently functioning lungs.
“There is a great deal of evidence that indicates that higher VO2max is associated with a decreased risk in the incidence of a number of lifestyle-related diseases, including breast, colon, and prostate cancer, cardiovascular diseases, type II diabetes, and Alzheimer’s disease,” Hungarian, Japanese and Finish scientists observed in a 2013, peer-reviewed study of oxygen uptake. “In accordance with this, an extremely low level of oxygen uptake could have serious outcomes such as increased incidences of diseases that lead to early death.”
A previously unknown pathogen believed to have evolved sometime in late 2019, SARS-CoV-2 is now methodically killing those with lower VO2max and lifestyle-related diseases. In Massachusetts, which has witnessed a major outbreak of the disease and carefully tracked the demographics of its victims, the average age of the dead is 82 and 98.3 percent suffered from an underlying health condition.
VO2max is a measure of a mammal’s ability to bring in and process oxygen. In humans, VO2max usually peaks in the 20s or early 30s, and then begins a steady decline, the extent of which is linked to activity levels.
Various studies have found a VO2max drop of less than 5 percent per decade to more than 10 percent per decade depending on the level of fitness training. Though the American Heart Association today advises that a low VO2max is associated with an increased risk of dying from any disease – not just COVID-19 – there is no inherent need for a high VO2max in today’s society.
Since most humans are no longer involved in running down wild animals on foot to feed themselves, it really doesn’t matter if a 40 year old has the VO2max of a 60 year old or a 20 year old. The decreased need might help explain the steady, global decline in cardiovascular fitness – the simplest, population-wide measure of VO2max.
“In the United States, kids’ cardiovascular endurance fell an average 6 percent per decade between 1970 and 2000,” scientists reported in 2013. “Across nations, endurance has declined consistently by about 5 percent every decade.”
This broad-scale, global, societal change could be read to buttress Greenhalgh’s argument for public masking not just for COVID-19 but in perpetuity if masks truly work to stop the spread of infectious respiratory diseases.
The CDC estimated 61,000 deaths from flu in the U.S. during the 2017-2018 flu season. That is near twice the number of Americans dying in motor-vehicle accidents every year with a five-year average of 35,945.
Motorists are now required by law to buckle themselves into their cars and trucks to minimize the death rate. If masks work, if masks can help to reduce deaths, why shouldn’t they be required at all times of everyone who goes out in public – just as seatbelts are now required?
If they work
Whether masks work is, however, a hotly debated question.
There are now studies underway to try to find some answers. A Chinese manuscript published by BMJ, formerly the British Medical Journal on Thursday, reported they do, at least when worn by family members of someone with SARS-CoV-2.
“Face mask use by the primary case and family contacts before the primary case developed symptoms was 79 percent effective in reducing transmissions,” Dr. Yu Wang from the Beijing Research Center for Preventive Medicine and his colleagues concluded.
There were, however, some confounding elements to the study.
“Wearing a mask after illness onset of primary case was not significantly protective,” the study said. The study does not make clear whether illness onset was defined by a SARS-CoV-2 test or symptoms of illness.
The idea behind public masking is that it protects everyone else from someone who has COVID-19. The authors offered no theories on why putting a mask on a COVID-19 suffered after illness onset showed no protective effect in keeping them from spreading SARS-CoV-2.
The study did make clear the value of social distancing and the big advantage it holds over masking.
“The risk of household transmission was 18 times higher with frequent daily close contact with the primary case,” the study said. It defined close contact as “being within one meter or three feet of the primary case, such as eating around a table or sitting together watching TV.”
Three feet is half the social-distancing recommendation in the U.S.
The study shed no light on how the disease might have been transmitted within the home, but noted “daily use of chlorine or ethanol-based disinfectant in households was 77 percent effective.”
Those disinfectants are used to clean counters, tabletops and more. Their effectiveness in lowering the spread of the disease would suggest there was some fomite spread going on in the homes, where it was also noted that “household ventilation” – an old Spanish flu prevention technique – was “protective.”
Ventilation serves to disperse and dilute virus aerosols. All of which brings the discussion back to droplets, aerosols and fomites in public.
I did my own little experiment in the South Anchorage Costco on Friday. I wanted to see how long it would take to count 100 people touching the fronts of their masks. It took approximately 14 minutes and 45 seconds.
No attempt was made to quantify mask touching activities by customers leaving Costco, where everyone is required to wear a mask, but the general observation was that most people pulled their masks off after leaving the store, and they usually pulled them off by the front.
One man pulled his mask off, always by the front, three-times in the liquor store. Several people left their noses hanging out. A couple appeared to have snot running down the fronts of the mask. Snot could be considered a giant SARS-CoV-2 droplet.
If any of these people were infected with SARS-CoV-2, they would have had it on their hands and spread it everywhere.
Researchers studying a SARS-CoV-2 cluster in a eight-story shopping mall in Wenzhou, China, concluded that the infections that popped up in people there who had no contact with known SARS-CoV-2 sufferers “could have resulted from spread via fomites (on elevator buttons or restroom taps) or virus aerosolization in a confined public space (restrooms or elevators). All case-patients other than those on floor 7 were female, including a restroom cleaner, so common restroom use could have been the infection source. For case-patients who were customers in the shopping mall but did not report using the restroom, the source of infection could have been the elevators. The Guangzhou Center for Disease Control and Prevention detected the nucleic acid of SARS-CoV-2 on a doorknob at a patient’s house….”
The possibility of picking up SARS-CoV-2 fomites while out of your home is the reason for the constant advice to wash your hands, wash your hands, wash your hands. Though fomite spread has not been proven, it would help explain the “community spread” cases of COVID-19 which happen to people who have no contact with a known SARS-CoV-2 carrier but come down with the disease anyway.
The real world
Randomized controlled trials to study masking in the real world are difficult to design and manage because of the many variables that come into play as the CEBM’s Jefferson and Heneghan observed.
“For starters, most of the trials were poorly reported and carried out during seasons of influenza-like illness when viral circulation is variable, but probably way below that (for SARS-CoV-2) in the Lombardy areas (of Italy) at the beginning of March. The design and execution of some of the trials were also questionable and as most were cluster-allocated, blinding was difficult, if not impossible.
“The trials carried out ‘in the community’ were in fact in specific settings such as halls of residence, family clusters or worshipping pilgrims.”
More studies are underway, but there might already be a simple, population-level comparison as to effectiveness available.
“Masks became a regular part of the street scene in parts of Asia after the deadly severe outbreak of acute respiratory syndrome (SARS) that started in China in 2002 before spreading to Singapore and Taiwan over the following year,” writes Ralph Jennings at Voice of America.
Taiwan is now all covered up.
“In the streets of Taipei, almost every second person wears a mask and on public transit nine in 10 if not more,” Jennings reported. “Hospitals and some schools in Taiwan require that anyone who enters wear a mask.”
Taipei is Taiwan’s capital city, and forms the core of the Taipei–Keelung metropolitan area home to roughly a third of Taiwan’s population. With a population o more than 7 million people, it is the 40th most-populous urban area in the world. The density of 25,000 people per square mile aids in the spread of any infectious disease.
Were mass masking significantly effective in slowing or stopping the spread of infectious disease, one would expect to see that reflected in annual mortality for the world’s most common, infectious respiratory diseases – pneumonia and flu.
Our World in Data includes other respiratory fatalities, such as flu, in the pneumonia number. The CDC lumps pneumonia and flu deaths together in the U.S, and reports a similar rate with individual states varying from a high of 29.6 per 100,000 (Hawaii) to a low of 9.6 per 100,000 (Florida).
More than 2.5 million people died from pneumonia in 2017, Our World in Data reported. “Almost a third of all victims were children younger than five years, it is the leading cause of death for children under five.”
Like SARS-CoV-2, pneumonia infects the lungs.
The COVID-19 death rate as of Saturday stood at 371,289, but the death toll continues to grow. Unlike with pneumonia, most of the victims are older. Of the 15,230 dead in U.S., only nine were 17 or younger, and only 610 were in the age class from 44 to newborn.
Nearly half – 7,419 – were age 75 or older, according to the website Worldometers. That is in line with data from China where the SARS-CoV-2 outbreak originated in late 2019.
Taiwan, at this time, is doing orders of magnitude greater than the U.S. in battling COVID-19, but the World Atlas website cites ten reasons for this starting with an early ban travelers from mainland China, prompt and early testing of any reporting flu-like symptoms, aggressive tracking of SARS-CoV-2 infections and strict quarantines for those who might have been infected, and more.
Sorting out the role masks play is difficult. On the one hand, some say they can’t hurt, although even that is not known for certain. On the other hand, some argue the lack of proven effectiveness isn’t worth the fear and social discord masks are generating.
You can now argue among yourselves.