When the Coronavirus arrived in the US, there was a rush by the public to acquire face masks. After all, the Coronavirus was a pathogen that caused disease by getting into the lungs by inhalation or by touching contaminated hands to the mouth, nose, or eyes. Face masks have the potential to filter particles and to deter touching one’s hands to the face. Wearing face masks thus seems a natural thing to do.
However, health policy officials chastised them and told them to stop buying masks. For example, the US Surgeon General tweeted on February 29, 2020, saying:
“Seriously people - STOP BUYING MASKS! They are NOT effective in preventing the general public from catching Corona virus, but if healthcare providers can’t get them to care for the sick patients, it puts them and our communities at risk!”~Dr. Jerome Adams, US Surgeon General.
Apparently, health "experts" believed that transmission to others involved symptomatic individuals with viral particles in their sneezes and coughs. The resulting sharp bursts of droplets contaminate the hands and belongings of the affected individual and collect on doorknobs, furniture, clothing and other surfaces. Hence, initially the public was only advised to wash hands and disinfect contaminated surfaces.
The snag in this logic is that virus transmissions from asymptomatic, but infected individuals, had been identified in the case of Coronavirus (Rothe et al. 2020), and found to be as much as 80 percent of all infections of others (Li et al. 2020). In March 2020, a summary of research on the mobility and characteristics of flu particles was published in the journal Aerosol Science and Technology. That literature made it clear that the Covid-19 particles of symptomatic and asymptomatic people were of the appropriate small size and persistence in the air to be inhaled deeply into the respiratory tract.
This is precisely the set of circumstances, of course, that wearing a mask to protect the wearer could have great benefit. The virus particles (or an important share of them) could be kept from entering the respiratory tract of the wearer. The importance of having the public wear masks is that the masks affect a pandemic at the virus’ first point of contact with people. Therefore, masks have the potential to immediately arrest the process that can cause the number of cases and deaths to grow out of control.
Health officials chose, instead, to practice social distancing. Unfortunately, this has meant shutting down many business and social activities. Some activities can be replicated by internet conferencing, but in the US, social distancing resulted in the closure of schools and increased the nation's unemployment rate to over 14 percent.
Japan’s experience with Coronavirus was very differemt. The Japanese public have a tradition of wearing masks every fall influenza season. Japan services this need by manufacturing 1.3 billion masks per year. At this writing, Japan has only one Coronavirus case for every 13,000 persons, versus the US with one per 500 persons. Japan also has a much lower death rate, at one death per 666,000 persons versus one death per 58,600 persons in the US). By these metrics, whatever the Japanese are doing is 26 to 77 times the US approach.
In addition, of course, the Japanese are not bearing the economic disruption that the US, the UK and others are suffering from the comprehensive social distancing policies. In contrast, at the theoretical extreme, effective masking could, by itself, not only control further spreading or rebound infections by Covid-19, but also control potential de novo or mutant airborne influenzas. Thus, a combination of comprehensive use of masks, frequent, periodic random testing to monitor the level and distribution of infection, and careful screening of US border crossings may be all that is needed going forward. It is also policy that can be activated and deactivated to quickly adjust to conditions.
Sources:
Asadi, Sima, N. Bouvier, A. S. Wexler, W. D. Ristenpart. 2020. “The Corona Virus Pandemic and Aerosols: Does COVID-19 Transmit via Expiratory Particles?” The Journal of Aerosol Science and Technology; Li, R., S. Pei, B. Chen, Y. Song, T. Zhang, W. Yang, and J.Shaman. 2020. “Substantial Undocumented Infection Facilitates the Rapid Dissemination of Novel Coronavirus (COVID-19).” Science. Rothe, C., M. Schunk, P. Sothmann, G. Bretzel, G. Froeschl, C. Wallrauch, T. Zimmer, V. Thiel, C. Janke, W. Guggemos, et al. 2020. “Transmission of 2019-nCoV Infection from an Asymptomatic Contact in Germany.” The New England Journal of Medicine. 382 (10):970–1.
