So much about the coronavirus has become political. People who wear masks are perceived by those who don’t as making a political statement…and vice versa. We are not interested in perceptions. We are interested in science. Do face masks work? Is there any science to support their use? What about oxygen restriction? Do face masks affect oxygen saturation?
A Reader Says Face Masks Restrict Oxygen!
Q. Why do the public health authorities keep telling us to always wear a mask? I have not seen any information showing that masks stop the spread of the coronavirus.
Instead, most of the info I have read says cloth masks do not block small aerosol particles. But they cut needed oxygen intake and raise CO2 intake.
Do Face Masks Work?
A. Masks do not provide 100 percent protection, but they are much better than nothing. The CDC reported an accidental experiment in which two hair stylists in Springfield, Missouri, developed symptoms of COVID-19 (MMWR, July 17, 2020). Both continued to cut hair while wearing masks. They interacted with 139 clients who also wore masks. None of the clients who were tested came down with COVID-19.
We admit that this “experiment” was not controlled. But most institutional review boards (IRBs) that must approve clinical trials would probably not permit scientists to carry out a study where people were exposed to the virus without masks. And of course such a study could never be “blinded.” People know whether they are wearing a mask or not. So, in this uncontrolled study the hair stylists demonstrated that face masks work.
An Observational Study: Did Face Masks Work?
A study in a large Massachusetts hospital system [Mass General Brigham (MGB)] found that when both patients and staff all wore masks, the rates of COVID-19 infection dropped dramatically (JAMA, July 14, 2020). This is the largest health care system in the state of Massachusetts. It has 12 hospitals and 75,000 employees.
The authors concluded:
“Universal masking at MGB was associated with a significantly lower rate of SARS-CoV-2 positivity among HCWs. This association may be related to a decrease in transmission between patients and HCWs and among HCWs [health care workers].”
In commenting on this research, public health experts point out that face masks serve two purposes: they protect the wearer against inhaling droplets and even some aerosol particles. They also trap particles being exhaled by infected individuals (JAMA, July 14, 2020). As a result, universal masking can help cut transmission. In other words, face masks work.
The Cleveland Clinic Study:
Investigators at the Cleveland Clinic, another huge health care system, assessed factors that affected infection rates (Journal of General Internal Medicine, Sept. 1, 2020). Over 70,000 health care workers (HCWs) were tested for SARS-CoV-2.
The conclusions:
“The overall proportion of COVID-19 positive tests in HCW was low and decreased during the study period corresponding with implementation of risk-mitigation measures in our health system such as the recommendations for universal masking and physical distancing but also followed the trend for non-HCW.”
Scientific Review: Do Face Masks Work?
An article in the journal the Science of the Total Environment (Aug. 7, 2020) reported:
“Notably, the uncertainties of face covering in protecting inter-human transmission, which have been emphasized by the WHO, have resulted in intensive debates on wearing face masks to prevent inter-human transmission during the pandemic and inconsistent recommendations by U.S. CDC and WHO. Evidence for the effectiveness of face covering has been recently recognized, showing reduced emissions of respiratory droplets and aerosols when worn by infected individuals and prevented inter-human transmission.”
Masks on Planes Cut COVID-19 Transmission:
On October 20, 2020, NPR aired a story on Morning Edition in which an epidemiologist looked at the transmission of COVID-19 on flights. Emirates airline has a universal masking policy that it enforces strictly. On several flights that included individuals identified as infected when they arrived in Hong Kong, no one else caught the coronavirus. The conclusion: masks work if everyone wears one. In that NPR clip, you can hear aerosol scientist Dr. Linsey Marr describe how she masks up when she has to fly.
Readers Disagree that Face Masks Work:
We know that many readers believe that face masks are worthless.
James states that face masks are ineffective:
“It is curious that pre-COVID studies testing the efficacy of masks seem to universally find them to be ineffective, even in the surgical suite. Post-COVID studies that have been cobbled together since the virus’s onset seem to universally support the wearing of even the flimsiest hankie. I don’t trust WHO, the FDA or JAMA so I choose to believe the non-agenda writers. Mask wearing is, at best useless and, at worst, harmful.”
Julie does not believe that face masks work:
“Every time you adjust your mask or touch it, you contaminate it. Then you touch something else like a jar on a shelf or whatever. You take the mask off and on repeatedly. It gets contaminated.
“Masks don’t work and at best provide a false sense of security and placate those who believe they do. Masks are ineffective and that is shown by real science, not reports by fame-seeking medical ‘experts’ who claim they are. Masks do cause harm despite those that claim otherwise – oxygen deprivation, headaches, allergic reactions and mask acne among other things.
“Those who want to wear one can do so and keep believing it is making them safe if they want to. The rest of us do not need to suffer with this ridiculous muzzling and violation of personal freedom.”
People’s Pharmacy Perspective:
Again, we emphasize that they are not perfect protection. At the time of this writing, over 8.2 million people have contracted COVID-19 in the U.S. and over 220,000 have died.
Countries that have embraced masks and other public health strategies have distinctly different statistics:
The John Hopkins Coronavirus Resource Center:
Taiwan: 535 cases and 7 deaths
South Korea: 25,275 cases and 444 deaths
Japan: 93,098 cases and 1,672 deaths
China: 90,972 cases and 4,739 deaths
We cannot verify the data except to say that The Johns Hopkins Coronavirus Resource Center data are more comprehensive than anything else in the world. And the countries listed above have, for the most part, opened up their statistics.
We welcome other suggestions for preventing COVID-19 transmission. If masks don’t work and social distancing is ineffective, what else can we do to slow the spread of this disease?
Do Masks Restrict Oxygen?
As for oxygen and CO2, a recent study found that face masks do not reduce oxygen or lead to carbon dioxide buildup (Annals of the American Thoracic Society, Oct. 2, 2020). This held not only for healthy volunteers, but also for those with COPD (chronic obstructive pulmonary disease), which makes it much harder for people to breathe.
The authors note that the idea that masks restrict oxygen is highly contentious:
“Current evidence, from observational studies to systematic reviews and epidemiologic modeling, supports the use of masks by the public, especially surgical masks, on mitigating COVID-19 transmission and deaths. However, public mask use has been heavily politicized with inconsistent recommendations by authorities leading to divided public opinion. Despite evidence to the contrary, an online UK/US survey found that only 29.7-37.8% of participants thought that wearing a surgical mask was ‘highly effective’ in protecting them from acquiring COVID-19. Another reason commonly argued against mask use involves safety concerns, as mask discomfort has been attributed to rebreathing CO2 and hypoxemia, with some even considering that masks are lethal.”
The Conclusions:
“…this data find that gas exchange is not significantly affected by the use of surgical mask, even in subjects with severe lung impairment. Our results agree with a prior observation on 20 healthy volunteers using a surgical mask for 1h during moderate work rates, in which mild increases in physiological responses also deemed to be of no clinical significance were observed.”
“It is important to inform the public that the discomfort associated with mask use should not lead to unsubstantiated safety concerns as this may attenuate the application of a practice proven to improve public health. As growing evidence indicates that asymptomatic individuals can fuel the spread of COVID-19,12 universal mask use needs to be vigorously enforced in community settings, particularly now that we are facing a pandemic with minimal proven therapeutic interventions. We believe our data will help mitigate fears about the health risks of surgical mask use and improve public confidence for more widespread acceptance and use.”
Final Words:
Science is not static. There will continue to be more studies. Only after we have accumulated lots of research will we have definitive answers to questions about the best ways to prevent the transmission of COVID-19. We will do our best to keep you informed as that research becomes available. Science should not be political. If you think this article is worth sharing, please send it to friends and families.
