A long post popped up on our social media feed during the Coronavirus pandemic, in summer 2020. It was just one of many posts spreading misinformation on social media about the effectiveness of mask wearing. Getting teens & tweens to social distance and/or wear a face mask is hard enough without extra problems caused by dodgy social media posts!
At this point in time, the evidence suggests mask wearing is probably effective at slowing the spread of coronavirus, though this evidence is not super-strong. This evidence is mechanistic, and highlights that wearing a mask would likely slow transmission by reducing the amount of droplets released into the air when we talk, sing, cough etc.
Many governments are advising the wearing of masks in enclosed spaces, such as shops and offices, to slow transmission of Covid-19.
We can summarise the current legitimate debate with the following questions.
Will asking the public to wear cloth face masks help to slow the transmission of coronavirus?
Are cloth masks harmful to the wearers?
TL/DR (Summary of this post): (1) Wearing face masks probably does help slow transmission of Covid-19, by what’s known as source control. Limiting how many people we infect, especially when we don’t know that we are infected. (2) Cloth face masks are not harmful.
This post was allegedly from Caitlyn, RN…
OPENING PARAGRAPH (P1) OF ORIGINAL POST – A nurse’s story, then the real study on cloth face coverings below. The WHO changed their tune on this, not after new scientific research, but after political lobbying 😦 Don’t bother commenting if you want to say PubMed is fake (from Caitlyn – an RN) Them: “But, Cait, don’t you wear a mask when you’re in the operating room?! YOU of all people should be advocating for people to wear masks!” Me: I’m so glad you asked! Let’s break down a few key points.
When writing a long message like this, the author knows people will rarely read beyond the first paragraph so we should look closely and ask questions that help us evaluate this post. It begins by stating it’s a “nurses story” and then links to [supposed] evidence about cloth face coverings.
The post claims that the WHO are an inconsistent source of information. It then makes use of a straw man argument to suggest that people say “PubMed is fake”. FYI, PubMed is just a search engine of medical studies. This is like stating “Some people say Google is fake”. We might critique what the articles it links to say… but no one is questioning PubMed or Google’s existence, its ability to find relevant documents or its convenience.
As for the WHO, Wikipedia describes the WHO (World Health Organisation) as ‘a specialised agency of the United Nations‘, its flagship publication the World Health Report informs “policymakers, donor agencies, international organisations… to help them make health policy and funding decisions“. So they probably know a bit about public Public Health. They give no evidence that the WHO are changing anything because of lobbying.
Who is Caitlyn and is she a nurse?
The text opens with an appeal to authority as the supposed author introduces herself as ‘Caitlyn, an RN‘. Followed by a lengthy story drawing on personal experience and 22 links to supposed evidence.
I do not know who Caitlyn is; she is not a friend of ours. She appears not to be a friend of my friend either. Her credentials, the initials RN might mean Registered Nurse. Earlier in the paragraph, the text referred to ‘a nurse’s story‘. Reading on, the post refers to 15+years of experience in healthcare, The post gives me no information about her level of qualification or country of qualification. The ‘appeal to authority’ is unsuccessful because there is no evidence of authority. She may not even exist.
The rest of the written ‘post’ is “Caitlyn’s story'”
Paragraph 2 (below) discusses masks being worn during surgery. This adds nothing to the debate about whether cloth face coverings are effective at slowing viral spread in the general population.
CONTINUED (P2) – One, in the surgery setting we wear masks for a couple reasons, none of which have much of anything to do with preventing the spread of viruses. The first is to prevent bacteria particles from our own nose and mouth from entering into the patient’s surgical cavity. This is not because anyone is sick. This is because we all carry pathogenic material in our airways, that normally are a non-issue, but when a patient is in a compromised state from being given general anesthesia and having their body sliced open, they become more susceptible to these opportunistic microbes we all carry. The second purpose of the mask in surgery is to prevent exposure of the provider to the patient’s fluids and tissue. Interesting to note, in many countries the circulating nurse doesn’t wear a mask, only those hovering over the surgical site don PPE.
Paragraph 3 (below) explains that surgeons [etc] wear masks to prevent them from infecting patients on the operating table. That’s not the issue here. The recent face mask advice aims to slow the transmission of Covid-19 from person to person in shops etc, and is not about protecting patients under our care, I don’t plan on operating on anybody, do you?
CONTINUED (P3) – Secondly, not all masks are created equal and most people have no idea which masks are for which circumstances, or that most masks provide little if any protection against viruses. The right mask worn incorrectly increases risk. The masks typically worn in the operating room are simply medical grade surgical masks, like the one I’m wearing here, and are not recommended for use when the presence of small particulate or aerosolized pathogens are in play. They’re great for keeping the teams spit out of the patients incision while they communicate during surgery and prevent chunks of tissue and blood spatter from being on the inadvertent lunch menu, but aside from that they’re really just little humid breath collectors. Instances when one would don an N95 respirator would be things like a case with a TB positive patient. And we are fit tested for those and given a specific mask type to use in such cases. The fit test consists of putting a giant plastic box over your head and spraying an aerosolized compound into the container while you wait to determine if your mask fit is good based on whether you can taste/smell the spray. It’s a big ordeal and redone each year in most facilities.
We found a 12-minute You Tube video from 2015 explaining the N95 fit-test referred to in this paragraph. It’s interesting as it shows that the “fit test” is irrelevant to our situation because the public are being asked to wear cloth masks to slow transmission to others, not protect themselves.
Paragraph 4 (below) warns us about PPE contamination, although gives no specific examples. Many countries have adverts running on national television and the WHO have a public information and awareness campaign, providing much more useful information on how to avoid such contamination.
CONTINUED (P4) – Last, in my 15+ years in healthcare, I have witnessed more improper use of PPE than I can quantify. I have seen seasoned medical professionals contaminate themselves and everything around them in a matter of seconds. Using equipment without the proper knowledge or training is a recipe for disaster and in this case, increased exposure. Unless you’ve thoroughly read through the literature and understand the approved uses, application and removal process, appropriate discarding protocols, etc you should probably just sit down and stop promoting inappropriate and unsafe mask use.
Paragraph 5 (below) warns us about masks harbouring germs in our airway. Again I’d follow the WHO advice on wearing and using a mask, not Caitlyn’s unevidenced rant.
CONTINUED (P5) – So if you’re not planning on doing some surgery while you shop for groceries or take a walk in the park, your mask is really just serving to warm your face and harbor some of those germs you’re so terrified of right in front of your airway. And if you’re wearing a sock or underwear on your face or rocking a bandana like we’re in the wild west, you’re simply creating more laundry for yourself, but doing absolutely nothing to stop the spread of pathogens.
Paragraph 6 (below) is concerning…
CONTINUED (P6) – And I have to say, I’m a little disappointed to see so many “educated” medical professionals promoting unsafe, baseless practices and seemingly forgetting their foundational knowledge😬
‘Educated medical professionals‘ like your doctor? Who may give you personalised advice based on your own medical conditions, and public health officials who have the very latest data on the virus, its spread, rate and mode of transmission, etc. I would trust my doctor over a random Facebook post any day.
CONTINUED (P7) – ***None of this even touches on the negative health impacts that can be caused from extended mask use, chronic fear and anxiety, and allowing others to make decisions for you because you don’t feel informed or empowered enough to make them yourself. I’ll save that for another post.
Finally, the post suggests there are ‘negative’ impacts of extended face mask wearing which are not reported in the mainstream media. As we will see, this post provides no evidence to support this claim. If there was actual evidence, reputable media organisations would fight to publish such a story.
The text also implies that we are not empowered or informed if we wear a mask. This is ironic considering a review of the evidence indicates that Caitlyn is not informing us, but instead misleading and misinforming us. Empowerment is about weighing the evidence and doing the right thing for yourself and your family, not following Caitlyn’s dictates.
So in summary, this is what we had done so far:
- We identified that the post is about cloth face coverings.
- In a long post like the publisher is hoping you only read the first few paragraphs. So we looked closely at that text and asked questions; Are the WHO? and PubMed? and are they reliable sources of information? Who is Caitlyn? Are her statements relevant and evidenced?
- We used Wikipedia to learn more about the WHO and identified that there was no evidence in this post to discredit it. PubMed is a search engine, so some results will be reliable, some less so. (just like with Google or Bing etc.)
- We identified that the message was making an ‘appeal to authority‘ and decided it was unsuccessful because there was no evidence of authority (We don’t know if Caitlyn exists, is a registered nurse etc).
(We later searched for the promised information pertaining to cloth face masks within the remaining text and found nothing.)
Usually, when we are presented with medical questions, we go straight to the relevant Cochrane review. But there wasn’t one available for cloth masks, so what did we do? Well, the next best thing is to review the studies themselves, often just reading a few paragraphs can tell to if its legit, relevant and actually indicating what people are saying about it.
So, let’s take a closer look at those medical study links… But wait!
SOME INTRODUCTORY TEXT FROM- Just a few studies about mask efficacy for those inquiring minds: It appears that several of the links originally included have been removed (surprise, surprise). But that’s ok, because there’s plenty more where those came from. Like these right here:
At this point we can see that someone appears to have edited the text along the re-post chain, adding the comment ‘several of the links..removed (surprise, surprise)‘. It is not clear who inserted this comment or why, and who they are accusing of removing the links; facebook? the government? other people who have received this and re-posted? And which links they have added or removed themselves.
The most important step to remember in order to evaluate the evidence found in the links is to remember the debate question: Will asking the public to wear cloth face masks help to slow the transmission of coronavirus? We aren’t criticising the studies. We are looking to see whether the 22 links can assist us to answer our question.
First, here’s a quick indication of the quality of the links:
- 3 of the links are broken
- 3 links lead to the same study (3 links does not equal 3 pieces of evidence)
- 2 links lead to studies documenting the dangers of sleep apnea and COPD (face masks are not part of either study)
- 3 of the links (4, 17, 21) lead to evidence that shows a potential benefit to wearing masks but are not strong enough in their findings to add to this debate
- Only link 22, which was broken, referenced a paper that might be related to our question. We located the study. The publisher had retracted it, because its statistics were ‘unreliable and [the] findings are uninterpretable‘.
After many hours of research, following the links and reading, we have no more quality evidence to inform us. This undated post is not a comprehensive overview of the literature available. It attempted to provide evidence for 1 side of the debate and didn’t even do this well.
So it isn’t even useful in providing a balanced viewpoint or even arguing one side. What a colossal waste of time! But what is more worrying, is that most young people and teenagers wouldn’t invest a day looking into this post, and most will only read the first paragraph and decide to ‘go with their friends view’, perhaps leaving a supportive comment and inadvertently promoting the post to others.
If you are interested, we have examined each of the 22 links below:
This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for HCWs, particularly in high-risk situations, and guidelines need to be updated.”
This is an interesting paper, and makes some excellent points about mask use in a hospital in Hanoi, Vietnam. The lead researcher was from Australia. In summary, the study shows that cloth masks are not great at stopping staff getting infected from patients, when compared to proper medical masks.
The clue is in the title: The aim of this study was to compare the efficacy of cloth masks to medical masks in hospital healthcare workers (HCWs). As the control group just used regular mask behaviour (which generally involved wearing masks) the study can’t reliably comment of cloth masks vs no-masks.
Here is an excellent article by the lead author of the above paper about cloth masks, here’s a good quote from the article:
“Modelling shows that even a modestly effective mask that delivers just a 20% reduction in viral transmission can successfully flatten the COVID-19 curve. Masks have a double benefit, stopping infected people spreading the virus and protecting uninfected people from catching it.”
Disappointingly, this links to the same paper as link 1.
This news article refers to a ‘rapid consultation’ from back in April in which the summary states there is no evidence either way yet, (the experiments haven’t been done). Studies of the masks and their behaviour suggest a cloth mask may stop larger droplets but not finer aerosolized particles, so they may not be massively effective at source control (They only stop 1 of the 2 causes airborne transmission routes):
“There are no studies of individuals wearing homemade fabric masks in the course of their typical activities. Therefore, we have only limited, indirect evidence regarding the effectiveness of such masks for protecting others, when made and worn by the general public on a regular basis.”
Cloth masks can increase infection
Yes, people can infect/contaminate themselves, e.g.:
“potential increased risk of self-contamination due to the manipulation of a face mask and subsequently touching eyes with contaminated hands;(48, 49)”
Much as if you touch your eyes after going to the toilet, before thoroughly washing your hands. But the document also lists benefits:
“reduced potential exposure risk from infected persons before they develop symptoms;”
From the WHO: There is limited evidence that wearing a medical mask by healthy individuals in the households or among contacts of a sick patient, or among attendees of mass gatherings may be beneficial as a preventive measure.14-23 However, 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.
The above is from a WHO document from back in April 2020 and refers to people themselves being protected from the virus through the use of masks. More recent guidance clarifies that cloth masks can help with source control. (ie: If you are infected and wear a cloth mask, transmission is slowed.)
Prolonged wearing of the surgical mask causes loss of intellect potential and cognitive performance due to a decrease in blood oxygen and subsequent brain hypoxia. Note – some changes may be irreversible.
This section appears to not be the work of “Caitlyn – an RN” but a copy and paste from the facebook page of a Naturopath in Texas.
If you look at his YouTube channel he talks about such things as how heart cancer doesn’t exist, here’s a Cancer Research UK article about how heart cancer is real.
“Report on surgical mask induced deoxygenation during major surgery” https://www.ncbi.nlm.nih.gov/pubmed/18500410
This study from Turkey does suggest a slight drop in blood oxygenation and increased heart rate when measured after surgery when surgeons wear an N95 mask. But it also states:
“This change in SpO2 may be either due to the facial mask or the operational stress, since similar changes were observed in the group performing surgery without a mask.”
“Seventy percent of the patients showed a reduction in partial pressure of oxygen (PaO2), and 19% developed various degrees of hypoxemia. Wearing an N95 mask significantly reduced the PaO2 level”
This study is of older men (Average age 57) undergoing hemodialysis due to end-stage renal disease and does not show a representative sample of the general population. Unless you are a 57yr old man undergoing hemodialysis due to end stage renal disease, you need not worry about hypoxemia and if you are, then you probably have bigger concerns than the debate about wearing cloth face masks in public.
“Wearing N95 masks results in hypooxygenemia and hypercapnia which reduce working efficiency and the ability to make correct decision.”..
“Medical staff are at increased risk of getting ‘Severe acute respiratory syndrome’ (SARS), and wearing N95 masks is highly recommended by experts worldwide. However, dizziness, headache, and short of breath are commonly experienced by the medical staff wearing N95 masks. The ability to make correct decision may be hampered, too.”
That’s just a link to a clinical trial record, (as mandated by US law), but I looked up the results of the trial. It’s a very small study where they put 10 healthcare workers on a treadmill for an hour. They wore 2 types of mask and a control group who wore no masks.
The results state:
“There were no significant differences between FFR and control in the physiological variables, exertion scores, or comfort scores.” The study’s only interesting result is that the air inside the mask had O2 & CO2 levels outside recommended levels, and that the vented masks weren’t much better. But this had no-effect on the blood oxygen levels of the poor people on the treadmills.
That link doesn’t work.
“Chronic hypoxia-hypercapnia influences cognitive function”
This study has nothing to do with masks, it is about how people with the lung disease COPD (typically caused by smoking and possibly air pollution) suffer from hypoxia and therefore become cognitively impaired.
“Hypercapnia status has been shown to predict mild cognitive impairment https://www.nature.com/articles/s41598-018-35797-3
This study is about overweight people with sleep apnea and has nothing to do with masks.
Chronic hypoxia – hypercapnia has been seen as a cause of cognitive impairment https://www.atsjournals.org/…/fu…/10.1164/ajrccm.186.12.1307
That link doesn’t work.
This was a large study that showed that there is no significant difference [in rates of Flu] between using medical masks versus N95 masks for outpatient treatment. It takes no position on whether people should wear masks in everyday life.
This is a meta analysis that concludes the same as the above, that there is not much difference between N95 masks and medical masks in clinical situations. It takes no position on whether people should wear masks in everyday life.
Another repeated link to the Hanoi, Vietnam paper we read in link 1. Three links to the same paper does not 3 pieces of evidence make!
Fit testing matters less vs it’s an N95 mask: https://www.ncbi.nlm.nih.gov/pubmed/21477136
This study suggests that N95 masks are more effective than regular medical masks, but says that there was not much difference when you look at the difference between ‘fitted’ masks and unfitted masks. It takes no position on whether people should wear cloth face masks in everyday life.
Masks don’t seem to impact family infection as much: https://www.ncbi.nlm.nih.gov/pubmed/28039289
This study actually concludes that:
“a potential benefit of medical masks for source control, but is limited by small sample size and low secondary attack rates. Larger trials are needed to confirm efficacy of medical masks as source control.”
Medical or N95 isn’t that different: https://www.ncbi.nlm.nih.gov/pubmed/31479137
Another repeated link
Cloth masks worse than surgical masks for anything <2.5 uM: https://www.ncbi.nlm.nih.gov/pubmed/27531371
It states cloth masks are probably not as effective as N95 masks for protection from diesel pollution. Again it’s not talking about either masks vs no mask or virus transmission.
Particle size breakdown and fabric differences for cloth masks and particle penetration: https://doi.org/10.1093/annhyg/meq044
This study suggests cloth masks are not as effective as N95 masks, but still have some effect.
“Our findings indicate that surgical masks can efficaciously reduce the emission of influenza virus particles into the environment in respiratory droplets, but not in aerosols”
So it stops larger droplets but not smaller ones.
It also states:
“Our results indicate that surgical face masks could prevent transmission of human coronaviruses and influenza viruses from symptomatic individuals.”
In conclusion, both surgical and cotton masks seem to be ineffective in preventing the dissemination of SARS–CoV-2 from the coughs of patients with COVID-19 to the environment and external mask surface.
This link is broken, but from the quoted text I looked up the article and it’s here:
The paper has been retracted, the reason being:
“values below the LOD are unreliable and our findings are uninterpretable.”