This question has come up again, most recently in an article appearing in the Washington Post yesterday that claimed that confidential sources in the government indicated the CDC is considering whether to make a recommendation that the public wear masks when they are out and about.
This past weekend, I ran to the store and saw a couple wearing masks. As a health care professional, I tend to look at these things opposite to how the public does. The public thinks the masks are for the protection of the person who is wearing the mask. Health care professionals realize that we put masks on patients to protect us from the person wearing the mask. I have to say that I was a bit unnerved when I first reacted and thought, “what are sick people doing out of their homes?!!” Then, I considered it further and suspected that these people probably thought they were protecting themselves from being infected while they were out in public.
So, first, let me be very clear. Wearing a cloth or even a surgical mask is very unlikely to prevent you from being infected by someone else with the coronavirus in a public setting.
As I wrote previously on my blog, a major mode of transmission of coronavirus is droplets, i.e., the small virus surrounded by secretions when it leaves the infected person’s mouth or nose. These droplets are big enough when leaving the mouth or nose to be caught up in the person’s mask. That is how a mask on the patient helps protect others around them.
On the other hand, by the time the droplet travels several feet in the air, much of the surrounding secretions fall on surfaces or the ground or evaporate and the small virus can easily penetrate these common masks being worn by the person who is not infected. Additionally, the risk, perhaps even the greater risk, is that someone touches the surface where the droplets have landed and places their hand to their mouth, nose or eyes allowing the virus to infect the person.
So, why would the CDC be considering making a recommendation that the public wear masks? Well, it appears that asymptomatic (or pre-symptomatic) persons with infection likely are shedding the virus for at least 1 – 2 days prior to becoming symptomatic. Further, we have some studies that show that normal breathing and talking spread droplets, not just coughing or sneezing. We still want everyone to cover their coughs and sneezes, because both of these probably propel droplets much further than normal talking or breathing, but covering coughs and sneezes may not be enough to prevent the transmission of this virus by droplets.
The problem is we curretly have no way of knowing who is infected, but asymptomatic or pre-symptomatic. Thus, if people who are feeling well are going to be allowed to go out in public for essential services, the only way to prevent them from spreading the virus to others would be to put masks on everyone so that those who are asymptomatic will be wearing a mask. That is certainly an appealing thought to further mitigate the spread of this virus.
However, there are also reasons not to take this step. First, it will be hard to change the public’s thinking that wearing a mask protects you from being infected. Thus, the fear is that people wearing a mask will be complacent and not perform other measures that are probably far more effective in preventing infection – social distancing and hand washing.
Second, we have a shortage of masks, and even though it is suggested that the recommendation would be for the public to wear cloth masks and homemade masks, my fear is that this will lead to faulty reasoning that if a homemade mask is good, a surgical mask will be better and an N-95 masks will be best. This would likely further compromise the supply of surgical and N-95 masks for health care professionals, who are the ones to most benefit from wearing masks.
Finally, while for some, wearing a mask will be a conscious reminder not to unconsciously touch our faces, for others, they may increase the touching of their faces while adjusting the mask and putting the mask on and taking the mask off for eating, drinking and entering or leaving their homes. This is likely to pose a greater risk of infecting the individual if they have not washed their hands well than going without a mask and social distancing.
Today, the recommendation is that persons who are well do not wear a mask out in public. We will see if the CDC changes this recommendation.