For most of the past two months,
Russian disinformation agents respectable Western Establishment voices such as the Surgeon-General of the US, the CDC, and the MSM (e.g. CNN, Vox) have churned out propaganda that masks are ineffective against containing the spread of the coronavirus. In perhaps the most “powerful” take, Forbes even claimed that they INCREASE infection risk.
This propaganda was bizarre on multiple levels. First, it violated common sense – even a T-shirt wrapped around your mouth and nose will ward off large droplets – there’s a massive amount of other evidence in favor of masks. Second, the conventional wisdom appears to be that this advice was given for a putative “greater good” – preventing runs on masks, so as to spare them for healthcare workers who are much more exposed to the virus. This, at least, made sense – though it had to be balanced against the negative impact on public trust towards “experts” and institutions. However, as Scott Alexander has noted, this explanation is likely false; in reality, the CDC and other American experts have been dismissing the efficacy of face masks for years, including during the H1N1 epidemic in 2009 and the MERS epidemic in 2015. So real explanation is much less altruistic and far more banal than even reasoned critics gave them credit for – it was just sheer bureaucratic inertia and unwillingness to adapt East Asian best practice.
In any case, there is evidence of a turnaround. Global mask production has been revving up, though East Asia remains far in the lead – China alone produces almost half the world’s masks at ~100+ million units per day, and its capacity to supply them will enable it to acquire massive soft power in the coming months. Moreover, an official recommendation to wear masks in public in the US appears to be imminent. The process is more advanced in several European states, such as Czechia, where according to Twitter, face mask adaptation has become near as universal as in East Asia.
This is very good news, if long overdue. Had these policies been adopted at the very start, it is entirely possible that the West not have seen the huge epidemics and morbid debates about whether to save the boomers or the GDP when a massive bunch of 5 cent face masks would have sufficed to keep r0 at close to 1. But this was left too late, and now there is no choice – POLITICALLY, at any rate – but to impose huge lockdowns that are going to crater the world economy (if only in the short-term… if we’re lucky).
The rest constitutes what I hope will be a useful reference on mask efficacy to convince people who insist that they are useless/won’t do anything/etc. Practical advice on face masks usage at my COVID-19 Survival Guide.
East Asian “Lived Experience”
Basic facts: No East Asian region outside Hubei, China – despite their FAR more intensive travel links with China – have experienced major COVID-19 epidemics as in Europe and the US. Not even South Korea, which experienced a freak occurrence thanks to Patient 31, a church-frequenting “superspreader.” Meanwhile, Japan has seen just a bit more than a thousand cases, despite adopting a very relaxed stance towards lockdowns, quarantines, and travel restrictions by global standards – there has not been a COVID-19 explosion as in Europe. Taiwanese cases capped out at 47, before Europeans started tilting their numbers modestly upwards again.
Balaji S. Srinivasan: “… Asia shows it doesn’t have to be this way. And their playbooks are online. So it’s bizarre to watch Western leaders surrender to the idea of 40-80% infection rates AND extended lockdown. That’s not a manageable situation, it’s overnight impoverishment.”
* Scott Alexander: Face Masks: Much More Than You Wanted To Know. Does a large meta-analysis of different studies to conclude that surgical masks are effective.
Meanwhile, n95 masks are more effective than surgical masks, but only if you put them on properly – which is apparently not a trivial task:
I remember my respirator training, the last time I worked in a hospital. They gave the standard two minute explanation, made you put the respirator on, and then made you go underneath a hood where they squirted some aerosolized sugar solution. If you could smell the sugar, your respirator was leaky and you failed. I tried so hard and I failed so many times. It was embarrassing and I hated it.
I’m naturally clumsy and always bad at that kind of thing. Some people were able to listen to the two minute explanation and then pass right away. Those kinds of people could probably also listen to a two minute YouTube explanation and be fine. So I don’t want to claim it’s impossible or requires lots of specialized background knowledge. It’s just a slightly difficult physical skill you have to get right.
Bunyan et al, 2013, Respiratory And Facial Protection: A Critical Review Of Recent Literature, discusses this in more depth. They review some of the same studies we reviewed earlier, showing no benefit of N95 respirators over surgical masks for health care workers in most situations. This doesn’t make much theoretical sense – the respirators should win hands down.
The most likely explanation is: doctors aren’t much better at using respirators than anyone else. In a California study of tuberculosis precautions, 65% of health care workers used their respirators incorrectly. That’s little better than the general public, who have a 76% failure rate. …
Is a poorly-fitting N95 respirator better than nothing? The reviewed studies suggest that at that point it’s just a very fancy and expensive surgical mask.
The surgeon general tweeted: “STOP BUYING MASK, they are not effective…”. The Center for Disease Controls (CDC) states that surgical masks offer far less protection than the N95 respirator masks (which also must be perfectly fitted and only professionals can do it). The CDC recommends that healthy persons should not wear masks at all, only the sick ones. These guidelines are not rooted in scientific rationales but were motivated by the need to save the valuable masks for health professionals in view of a shortage. But they may have had unintended consequences: stigmatizing those that wear masks in the public (you are a hoarder, or you are contagious!)
Contrast this with the cultural habit, the encouragement, or even mandate to wear masks in Asian countries — which have now “flattened the curve” or even have had a flatter curve from the beginning.
* Less Wrong: Credibility of the CDC on SARS-CoV-2
* Yan, Jing, Suvajyoti Guha, Prasanna Hariharan, and Matthew Myers. 2019. “Modeling the Effectiveness of Respiratory Protective Devices in Reducing Influenza Outbreak.” Risk Analysis: An Official Publication of the Society for Risk Analysis 39 (3): 647–61.
It was found that a 50% compliance in donning the device resulted in a significant (at least 50% prevalence and 20% cumulative incidence) reduction in risk for fitted and unfitted N95 respirators, high-filtration surgical masks, and both low-filtration and high-filtration pediatric masks. An 80% compliance rate essentially eliminated the influenza outbreak.
* Davies, Anna, Katy-Anne Thompson, Karthika Giri, George Kafatos, Jimmy Walker, and Allan Bennett. 2013. “Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic?” Disaster Medicine and Public Health Preparedness 7 (4): 413–18.
The median-fit factor of the homemade masks was one-half that of the surgical masks. Both masks significantly reduced the number of microorganisms expelled by volunteers, although the surgical mask was 3 times more effective in blocking transmission than the homemade mask.
* Radonovich, Lewis J., Jr, Michael S. Simberkoff, Mary T. Bessesen, Alexandria C. Brown, Derek A. T. Cummings, Charlotte A. Gaydos, Jenna G. Los, et al. 2019. “N95 Respirators vs Medical Masks for Preventing Influenza Among Health Care Personnel: A Randomized Clinical Trial.” JAMA: The Journal of the American Medical Association 322 (9): 824–33.
In this pragmatic, cluster randomized clinical trial involving 2862 health care personnel, there was no significant difference in the incidence of laboratory-confirmed influenza among health care personnel with the use of N95 respirators (8.2%) vs medical masks (7.2%).
* Leung, Nancy H. L., Daniel K. W. Chu, Eunice Y. C. Shiu, Kwok-Hung Chan, James J. McDevitt, Benien J. P. Hau, Hui-Ling Yen, et al. 2020. “Respiratory Virus Shedding in Exhaled Breath and Efficacy of Face Masks.” Nature Medicine, April. https://doi.org/10.1038/s41591-020-0843-2.
Your Lying Eyes
Researchers from Bauhaus-Universität Weimar, Germany made the following video illustrating the flow of droplets from normal breathing, coughing, and coughing into a hand, an elbow, a dust mask, and a face mask.