Yesterday I offered a somewhat lighthearted attempt to get people to wear masks anytime they are in a public place. Today, I thought I’d give the scientific arguments and an urgent plea to do this simple task.
Wearing a mask is the most effective way to prevent the spread of COVID-19. It is a respiratory virus, and transmission now is almost entirely associated with respiratory droplets, spread from human to human. Multiple episodes have documented respiratory spread, accentuated by close contact between many individuals. Activities that increase respiratory droplets have also augmented transmission and created “super spreader” events. Indoor activities, where there is no breeze to disrupt respiratory aerosols, are shown to increase the likelihood of COVID-19 infection and add credibility to respiratory and aerosol transmission.
Some of the best documentation that universal masking can markedly prevent transmission of COVID-19 comes from a recent study conducted at a major health care institution In Massachusetts. Health care workers had a progressive decrease in the acquisition of COVID-19 once universal masking was put in place in these hospitals. This decrease was present even when controlling for other factors involved in COVID-19 transmission. Remarkably, despite these health care workers having significant ongoing work exposure and using excellent protective equipment, there was still a decrease with universal masking of people in their hospital. One could hypothesize that in places such as stores, restaurants, or bars where other protective measures aren’t occurring the benefit from masks would be even greater.
The concept that the disease would be spread by coming into contact with the virus on various surfaces was always a stretch and appeared based on theoretical ideas that came from articles that showed the virus might survive on some surfaces for a period of time. There has been no single case documented that someone infected themselves with COVID-19 from touching a surface that had been previously, accidentally contaminated with virus.
I think the CDC made major mistakes by giving varied, different instructions to people about COVID-19 avoidance. These instructions were confusing and oftentimes internally inconsistent. This contributed to the public’s reluctance to wear masks. Finally, the CDC has now cut the talk about decontaminating surfaces and focused on preventing COVID-19 by wearing masks. In an editorial in JAMA about the Massachusetts healthcare study, written by three authors from the CDC including the director (Dr. Redfield), the agency strongly supported universal masking. Redfield has also said publicly that the pandemic could be brought under control over the next four to eight weeks if “we could get everybody to wear a mask right now.” If he had made that kind of statement months ago we would be in a much better situation right now.
Masking should not be considered a political statement. In fact, the best thing one could do for the economy is to have universal masking since this would allow the most significant return of economic activity and prevent having to completely isolate and stay at home. It would also reduce healthcare costs and allow those resources to be used to support other parts of the economy. Universal masking allows freedom of movement to a degree not achieved with any other protective approach. Masking therefore has positive attributes for every part of the political spectrum.
A recent article on the efficiency of different types of masks makes for interesting reading. A review of face masking in the WSJ that references the article also has an excellent figure on the efficiency of different types of masks (modified above).
Regardless of what you choose, just wear a mask. The infection you prevent might just be your own!