Wearing Masks in Public Should Be Mandatory-Now!
To curb the spread of the Novel Coronavirus pandemic COVID-19, on April 3rd, 2020 the US Centers for Disease Control and Prevention finally advised Americans to voluntarily wear a basic cloth or fabric face mask when they go out. However, this advice is only voluntary, as demonstrated by President Trump during the daily Coronavirus Task Force briefing on the day of the announcement. He said “I am feeling good, I just don’t want to be doing it…. I won’t be doing it personally”. As a result, most of his followers might choose not to do it either, thus significantly lower the effectiveness of this recommendation. In fact due to cultural inertia the general public in most Western countries is still quite reluctant to wear a mask in public, resulting in a sluggish “flattening of the curve” in spite of much effort on “social distancing”. Here by “in public” we mean the situation of potential close human physical interactions such as in a grocery store, a pharmacy, a subway car, other public transportation means, an elevator, an opened restaurant, an opened shopping mall, a working factory, a working office, etc.
In this article, I present analytical data to show the difference between wearing and not wearing masks in public. The original COVID-19 data source is from Worldometers.info [1] which updates the information daily or even hourly. To compare the situation among different regions with different populations it is more appropriate to normalize the data with population by region. I have done so throughout this article. In the following discussion the data will be presented as number of death or number of confirmed COVID-19 cases per one million people of the region.
Difference between Wearing and Not Wearing
The difference is shown in Figure 1 with data on April 4, 2020, one day after the US CDC announcement.
In this graph I present the data by plotting the number of COVID-19 death per one million people vs. the number of confirmed COVID-19 cases per one million people. To read this graph, those at the lower left corner have the lowest COVID-19 incidences, and those nearest the upper right have the highest. I show a big group (encircled with a dashed red oval) of eight: USA, UK, Germany, France, Belgium, Netherlands, Italy and Spain, whose residents do not wear masks or only sparsely do so in public in general. In comparison, I also present data of China, including Taiwan and Hong Kong SAR (Special Administrative Region); S. Korea, Japan, and Vietnam, whose residents all choose to wear masks in public at the very beginning of their outbreak of COVID-19.
The reason that the residents immediately jumped to wearing masks is due to their painful experiences of the SARS (Severe Acute Respiratory Syndrome) epidemic 17 years ago. During the SARS epidemic in Hong Kong, 76% of the population was wearing a mask [2]. In fact at the onset of their COVID-19 epidemic masks were out of supply overnight as people rushed out to buy them. “Over the past week, people living in Singapore, Shanghai, and Hong Kong claim masks have sold out at most local shops.””Many of them are uploading photos and videos of the insane queues that are forming in stores that are still offering precious stocks of the item”[3]. Their governments and private entrepreneurs immediately ramped up the production of masks, particularly of surgical face masks since they are the ones that are effective and can be mass produced [4]. In Vietnam garment factories switched into making special cloth masks to meet domestic and international demands [5]. Mask wearing has become a ubiquitous sight [6].
It is obvious in this graph that the group with its residents wearing masks in public is located very close to the lower left corner of the graph (corner group encircled with dashed blue oval), has very low COVID-19 incidences, and is well separated from the other big group. The big group with its residents not wearing or sparsely wearing masks is relatively scattered, but has very high COVID-19 incidences. The scattering might be due to the different timing of outbreak, the different extent of seriousness to which the governments took the situation at the beginning and how soon actions were taken, the extent of COVID-19 testing, of contact-tracing, of case isolation and of social distancing, as well as cultural habits and individual attitudes [6] towards the crisis.
It should be noted that out of the corner group, in the case of S. Korea (the one farthest out to the right), about half of the cases were due to super-infection in a Shincheonji Church of Jesus Christ which banned wearing masks [7]. Excluding them would cut the number into half. The next one in is Hong Kong SAR. Hong Kong SAR is the second or third most populated region in the world. It is more difficult for its residents to practice real social distancing due to huge population density. Yet about half of its cases are imported. Thus Hong Kong has actually done an excellent job of diminishing community transmission of the virus. The third one in is China. Facing a then unknown brand new virus, China suffered an initial fumble due to local bureaucracy, just like most Western nations later even with ample prior warnings. As soon as its human-to-human transmission was confirmed on January 20, 2020[8], China jammed the breaks and closed down the city of Wuhan on January 23rd, 2020. Now it has a very low per capita number of death (2.3 per million) and number of cumulative cases (57 per million), with 94.5% already recovered. This is partly due to the “dilution” effect by its large population. However in contrast to what is currently happening in the US today, the fact that it was able to stop the rapid spread of the virus to the rest of the nation played a major role. The swift adoption of mask wearing in public by the general public in China contributed significantly. For comparison, in Hubei Province, the China epicenter province where Wuhan city is located, the per capita death stopped at its maximum of 55 per million and the confirmed cases stopped at the maximum 1,159 per million. On the other hand, in New York State, the US epicenter state where NY City is located, the current death is 481 per million and the number of confirmed cases is a staggering 9,174 per million (data on April 12, 2020 [1]). Overall as of April 12, 2020, the number of death in China is 2.3 per million and the number of confirmed cases is 57 per million; while in US the number of death is 67 per million and confirmed cases is a striking 1,692 per million! By the time this article is published the numbers in the US will be higher, and at the current trend will still be growing rapidly.
COVID-19 Progression in 4 Days
The rapid growth can be visualized with a “snapshot” of the situation over just 4 days.
In Figure 2 I show the progression of the situation from April 4th, through April 6th to April 8th, 2020. The choice of these particular days is immaterial; any other choices will yield a similar picture. For clarity, we plotted three points for each region. The number next to the points indicates the number of death per one million people. The separation between two adjacent points shows the changes in just two days: The farther apart the two adjacent points, the more serious the situation. Each group of three points is labeled with its name. Once again, for the lower left corner group there is practically near-zero change between the adjacent points. The epidemic is under control. On the other hand, everyone in the big group not wearing masks still suffers dramatic daily-increasing casualties.
Mandatory Policy of Czechia and Slovakia
One noticed that not all European nations were reluctant to change their habits in order to fight the virus. Both Czechia and Slovakia had adopted a policy of mandating their residents to wear masks in public in March 2020. Therefore I presented these two in Figure 3.
It can be seen that the separations of their three data points are very small, indicating that the growth is much slower than anyone in the big group. We just learned that Bosnia-Herzegovina and Austria have joined the rank of mandatory mask wearing in public.
Mandating mask wearing in public also has the advantage of policy enforcement easier than that of “social distancing”. After all, if in public I see you wearing one and you see me wearing one, we both will feel comfortable toward each other during the pandemic. Both of us or a third party can help to enforce the exercise of this policy at a personal level. It is human nature to interact with one another. When friends meet or when people work by interacting they want to speak to each other. Mask wearing is the only means to accommodate this safely.
Mathematical Principle of Masks Wearing by the General Public
One may ask: Why does “masks wearing“ work?
It is mathematically simple to explain why mask wearing by the public works. The principle is given below.
Most people know that the N95 mask is the high(est) standard in filtering out microscopic particles if properly fitted to one’s face. Let’s assume that the N95 mask can filter 95% of the culprit, thus the virus transmissivity is reduced from 1 to (100% -95%=) 0.05 by wearing a N95 mask. A recent scientific study published in Nature showed that the surgical face mask is effective in reducing virus transmission [9]. A surgical face mask is loosely fitted to the face and has lower capability of filtering than N95. It usually has a middle layer of Filtret in it. For argument’s sake, let’s say its efficiency is only 85%, thus the virus transmissivity of a single mask is (100%–85%=) 0.15. When two people meet, if only one of them wears a surgical mask, the transmissivity remains 0.15. However if both wear the masks, the transmissivity will be reduced to (0.15X0.15=) 0.023! This is much smaller than just reducing it by a factor 2 or (0.15/2=) 0.075. It is even lower than 0.05. In other words, the case of an emitter wearing a mask and the receiver wearing a mask is equivalent to putting two surgical masks in tandem, but without sacrificing its breath-ability. We call this “multiplying reduction effect”. It is by multiplying the two reduction factors.
A similar argument can extend to wearing well constructed cloth masks preferably with a Filtret insert: We know that the virus particle though extremely small, is not a living thing. To reach another person, it must be carried by a medium, such as cough/sneeze droplets (or in the rare case aerosol droplets generated in the hospital). Cloth masks are well suited to block aqueous droplets. So let’s assume a single cloth mask is only 75% effective, with transmissivity of (100%–75%=) 0.25. With both the transmitter and receiver wearing this type of masks, the resulting transmissivity is reduced to (0.25X0.25=) 0.06! If one person wears a surgical face mask and the other person wears a cloth mask, then the net transmissivity will be (0.15X0.25=) 0.0375, again much lower than 0.05. Please note that the actual values of transmissivity of N59 mask, surgical face mask and cloth mask need to be determined experimentally and may also be direction dependent. The physics of filtration is more complicated, the mathematical principle nonetheless remains the same.
Of course, all the precautions of handling and wearing a mask, such as not to touch the front side of your mask etc. must still apply. In addition, cloth masks must be replaced with clean ones with new inserts every day. The used one can be treated with boiling water to “kill” the virus easily. We will not elaborate on the detailed protocols here, but just provide the fundamental principle.
Would an advice of voluntary mask wearing work?
The answer is no, not effectively. As we have stated above, when two people meet, if only one of them wears a surgical face mask, the transmissivity remains whatever value a single surgical mask has. There is no “multiplying reduction effect”. A voluntary advice will leave the other half of population not wearing masks and thus defeat the “multiplying reduction effect”. To achieve the “multiplying reduction effect” both parties must wear masks. Therefore this strategy will work only by mandating mask wearing in public and getting buy-in from the general public.
Conclusion
In conclusion, along with existing measures of isolating, disinfecting, hand-washing and social distancing, mask wearing in public by the public is an effective means to prevent the spread of the virus. Mandating this policy is the way to effectively implement this policy.
It is now well known that asymptomatic and pre-symptomatic COVID-19 carriers can be up to 25 to 50% of the confirmed cases. As these “silent” carriers are able to spread the virus, silent-source control becomes paramount. Even though the US CDC has announced an advice of voluntarily wearing home-made masks or bandannas in public, it is far too weak and far too slow to be effective. This advice might be a result of compromises due to the dwindling supply of masks. It is absolutely correct that we must give the highest priority to our frontline health care workers, nurses, doctors, medics, police officers, hospitals, clinics, etc. Therefore in view of the supply shortage of masks it is understandable and correct to preach “social distancing” as a weapon for fighting the pandemic. The partial success of social distancing however may have delayed the effort to ramp up the mask supply and to implement a mandatory policy of mask wearing by the general public. One must not overlook its effect on diminishing the source of patients, as a true way of not overloading our frontline defenders and our limited medical infrastructure. Along with other measures, ramping up the mask supply for the general public is probably the cheapest way to fight the pandemic.
To avoid a second wave of infection, mandatory mask wearing in public by the general public will also be a must for opening up the economy. When the economy is opened up, human physical interaction will inevitably be closer. By implementing a mandatory policy of mask wearing now, a new culture can be established; its momentum will be carried by the general public to the time when the “stay-at-home” order is lifted.
While people and policy makers are still debating, the SARS-CoV-2 virus that causes COVID-19 relentlessly advances at an exceptionally high speed, disregarding race, gender, age, religion, belief, political system, party affiliation and international boundary… Time is critical. Each single day of waiting translates into drastically dire consequences.
References
[1] https://www.worldometers.info/coronavirus/ (Its data is collected from official reports, directly from Government’s communication channels or indirectly, through local media sources when deemed reliable. Its data is trusted by UK Government, Johns Hopkins CSSE, Financial Times, The New York Times, BBC…)
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3367357/ Emerg Infect Dis. 2005 Nov; 11(11):1738–41, JY Lo, et.al. “Respiratory Infections during SARS Outbreak, Hong Kong, 2003” Nov 2005.
[3] https://www.businessinsider.com/wuhan-coronavirus-photos-people-queuing-up-face-masks-across-asia-2020-1. R G Chia, “Photos Show Hundreds of People Queuing up for Face Masks across Asia, as Coronavirus Spreads” Jan 30, 2020.
[4] https://insideevs.com/news/404692/byd-world-largest-face-mask-factory M Kane, “BYD, one of the biggest EV Manufacturers, Produces Millions of Face Masks to Support the Fight with the COVID-19 Outbreak”. March 17, 2020.
[5] https://vietnamnews.vn/economy/653289/garment-firms-shift-to-produce-antibacterial-masks-to-meet-demand.html, March 09, 2020
[6]https://www.bbc.com/news/world-52015486 T Wong, “Coronavirus: Why Some Countries Wear Face Masks and Others Don’t” March 31, 2020
[7] https://www.statista.com/statistics/1103080/south-korea-covid-19-cases-related-to-shincheonji-church/ “COVID-19 Cases Related to Shincheonji Church South Korea 2020”, April 14, 2020
[8] https://www.theguardian.com/science/2020/jan/23/coronavirus-timeline-from-wuhan-to-washington-state “Coronavirus Timeline: from Wuhan to Washington State”. Jan 22, 2020.
[9] https://www.nature.com/articles/s41591-020-0843-2#citeas N. Leung, et.al. “Respiratory Virus Shedding in Exhaled Breath and Efficacy of Face Masks”, Nature, April 03, 2020
