COVID-19 Day 5: Why the CDC Should Encourage Face Masks.

The CDC strongly discourages healthy people from wearing N95 masks. Instead their primary advice is that people should hand-wash frequently. But even the CDC admits that few actual cases have been spread from an infected surface; the virus spreads from via close-proximity airborne transmission. Hand sanitizing will not protect you from breathing in the virus.

The CDC’s anti-mask advice is coldly pragmatic. We need the N95 masks to protect health care workers treating COVID-19 patients and there are not enough N95 and surgical masks available. Manufacturers have been ordered to step up production and regulations have been relaxed but the shortage remains acute.

N95 respirators (masks) filter out 95% of particles larger than 0.3 microns and are designed to protect the wearer from contracting pathogens. They are different from Surgical and Procedural masks which are the common disposable masks worn at hospitals. Surgical masks work in the opposite way. They aren’t designed to protect the wearer from patients pathogens. They’re designed to protect patients from the wearer.

But why should “healthy” people wear masks if they’re not infected with COVID-19? Because they are probably infected but don’t know it. COVID-19 has a long incubation period of up to 14 days (with a median of 5.2 days). A study published in the journal Science, suggests up to 75% of new Covid-19 infections have been spread by people who were asymptomatic; they didn’t have symptoms and didn’t know they were infected. Wearing a masks helps prevent asymptomatic spread.

Where surgical masks were in short supply, home-made/DIY (Do-it-Yourself) masks can be used effectively. A Cambridge study found that DIY face masks made from a single layer of a 100% cotton t-shirts were capable of capturing ~70% of virus droplets exhaled by test subjects. While not as effective as a surgical mask, it is certainly better than no mask at all. And improvements in DIY mask design and construction could quickly be developed.

The CDC’s other argument against healthy people wearing masks is that the average person doesn’t know how to wear a mask properly and it creates a false sense of security. Similar reasoning was once leveled against automobile seat belts, predicting that people would drive more recklessly if they wore them. Could you imagine if the CDC treated hand-washing with a similar attitude: ‘people will wash their hands wrong, so we discourage them from doing it.’

Instead, medical professionals went on a focused effort to promote frequent hand-washing and educate the public on hand-sanitizing techniques. A similar program to encourage public mask wearing could easily be established along with their other advice: “Wash your hands”, “Don’t touch your face”, “Social Distancing”, “Stay at Home”,  and “Wear a mask if you go out”.

A close comparison study should be made of COVID-19 spread in European countries were face mask wearing is discourage and Asian countries where face mask wearing is culturally acceptable. Other factors obviously play a role in slowing the spread of COVID-19, such as testing, quarantine measures, shut-downs, et al. Like it or not, we’re living a real time infection control experiment that none of us wants to get wrong.

 

How easily droplets can be expelled just by breathing and talking vs. wearing a mask.


SOURCES

https://www.eurekalert.org/pub_releases/2020-03/cums-tf031520.php

https://www.cdc.gov/niosh/npptl/pdfs/UnderstandDifferenceInfographic-508.pdf

https://www.crosstex.com/sites/default/files/public/educational-resources/products-literature/guide20to20face20mask20selection20and20use20-202017.pdf

https://academic.oup.com/cid/article/49/2/275/405108

https://www.cnn.com/2020/03/14/health/coronavirus-asymptomatic-spread/index.html?fbclid=IwAR0DBT3nqU1R_RR7Vrd6CztrStg7vqRlXn5qNobZoO4lZM2Cd63tHAOu9HQ

https://academic.oup.com/cid/article/49/2/275/405108

https://www.researchgate.net/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic

https://smartairfilters.com/en/blog/best-materials-make-diy-face-mask-virus/

https://www.cdc.gov/coronavirus/2019-ncov/hcp/respirator-use-faq.html

https://academic.oup.com/cid/article/49/2/275/405108

https://www.researchgate.net/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic

http://www.cidrap.umn.edu/news-perspective/2020/02/unmasked-experts-explain-necessary-respiratory-protection-covid-19

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