Two Aggies, a Longhorn, and a Nobel Laureate…
For the TLDR crowd: Many people infected with SARS-CoV-2 have no symptoms. Mask wearing is likely the key to minimize COVID-19 spread by asymptomatic patients and rescue our economy.
A person infected with COVID-19 may spread this illness through the production of aerosol or droplets. Aerosol and droplet production is more likely with sneezing or coughing, but also with loud conversation or singing. It is likely that COVID-19 is transmitted primarily by droplets, less frequently by aerosol, and rarely (if ever) by contact with a contaminated surface.
At a choir practice in Washington State where one member had COVID symptoms, the majority of the choir was infected following a 2.5-hour practice. (2)
Because droplets are larger (>5 μm) and heavier, they do not travel as far and tend to settle to surfaces within about 1.5 meters of the infected individual.
Researchers (the improbable combination of 2 Aggies, a Longhorn, and 2 Californians - one a Nobel Laureate) analyzed the course of disease spread in relation to stay-at-home orders, social distancing, and face-covering orders.
They concluded that airborne spread is the dominant mechanism of disease transmission. Most agree; the consensus among experts is that contact with contaminated surfaces is not a primary mode of disease spread. The same researchers concluded that face coverings were the most effective mitigation measure because they decrease the aerosol spread of the disease; this has also become a clear consensus opinion among experts.
The image above depicts the number of new cases reported in New York (panel A) compared with the rest of the United States (panel B).
British researchers simulated various behaviors and concluded that in all scenarios studied, face mask use by the majority of the population would result in decreased infections over time. A group in Germany reached a similar conclusion based on observing the rate of spread of disease.
A study published in April showed that unfitted paper surgical masks decreased aerosol spread of seasonal coronavirus (structurally similar to COVID-19). And authors of a recent article in the New England Journal of Medicine produced a helpful accompanying video.
Need a haircut? Wear a mask.
Two hairstylists in Missouri worked while unknowingly infected with COVID-19. Masks were recommended (and reportedly uniformly used) by the stylists and customers. The number of infections among their 140 customers and six colleagues: zero.
We all miss travel
Similarly persuasive is population-based data. Researchers in Hong Kong report a detailed analysis of the impact of mask-wearing. With Hong Kong’s population density and shared border with China, a devastating outbreak would have been expected. But in response to SARS-CoV-1 (that caused the SARS), much of Asia learned to wear masks to protect against the spread of diseases. The instinctive reaction to COVID-19 was to don face coverings promptly.
As of 06/27/20, the number of cases and deaths per million population by country includes:
To address a social-media myth: paper surgical masks or home-made face cloth coverings do not decrease the wearer’s ability to obtain oxygen and exhale carbon dioxide. Physicians, dentists, nurses, and many craftsmen wear them for hours at a time. And if you think a face covering is uncomfortable, you would certainly hate mechanical ventilation.
Speeding in a school zone?
The resistance to mask-wearing is the result of misinformation and terrible messaging from public health authorities. Here’s how we’ve explained the issue:
Many people will occasionally exceed the speed limit on the highway. We know we are taking a small personal risk in doing so. At the same time, almost none of us would speed in a school zone.
If you occasionally exceed the speed limit on the highway, but would never do so in a school zone, you should wear a mask in public.
Not to protect yourself (though they probably do), but to protect others. Particularly those more vulnerable to this disease (much like you don’t speed in a school zone to avoid injuring a child who runs out in the street).
There has been so much misinformation on this topic. When Americans realize they wear a mask to protect others, most will do so. Because we are Americans. And we protect each other - particularly the vulnerable among us.
As we each consider how to protect ourselves and those around us, we should consider the impact of public health decisions on businesses and the economy.
Until we have an effective vaccine, public health tools to prevent the spread of COVID-19 are limited primarily to face covering and economic restrictions (closing businesses, etc.) to enforce social distancing.
If we can achieve mass adoption of face covering, we may be able to avoid the business restrictions which have so damaged our economy.
06/30/20 Edited to add: a Goldman Sachs published a report this morning suggesting that a national mask policy would save the US economy $1T relative to renewed lockdown measures to deal with COVID-19.