by Michal Kulon, MD

• Prevention is the key, not treatment.
  Doctors can't cure COVID-19. There is no vaccine or reliable drug, and no hope that these will be developed or available within several weeks, when COVID-19 will gradually start causing thermonuclear-scale devastation in USA. It is rapidly spreading, exponentially doubling the number of infections every 3-4 days. Without preventive measures, many millions of fatalities are expected in the USA. With the current half-baked social-distancing platform that doesn't even apply to teens and other carefree adult children, the deaths are likely to be in hundreds of thousands, exceeding the number of lives that have been lost in nuclear bombings. Many of those infected cannot breathe on their own. Some can be saved by artificial ventilation during the worst period of their disease, but some will die despite this. Based on all estimates, and on the experiences in Italy and China, the onslaught of the sick COVID patients will crush hospital capacities by a factor of roughly 8-fold. The number of ventilators will be grossly inadequate, even despite risky efforts of connecting several patients to a single machine. Numerous people will die over the next 2 months because they were needlessly infected, and a ventilator will not be available when they are unable to breathe. Some panels of experts have reached the chilling conclusions that, in order to save multiple other people, precious and limited ventilators should be denied to those who are estimated to need them for a longer period of time, or those who have lower chances of recovery, and that some patients may need to be disconnected from their ventilator and thus murdered, not because they are a hopeless case, but instead because their ventilator needs to be used for other lower-risk or younger patients. While this may sound logical when discussing hypothetical abstract patients, who would tolerate losing their loved one in this manner or being themselves subjected to this?

• Countries and cities which succeeded in halting the rapid viral spread among their citizens have encouraged or mandated everyone to wear masks in public: China, Wuhan, South Korea, Singapore, Hong Kong. However, in USA, we think that we know better, an attitude that has made USA the #1 most COVID-infected nation in the world, in terms of absolute numbers, and also near the top of the list for the percentage of population who have been infected, surpassing China. Production of more ventilators is helpful, but these would not be even needed if prevention and hindrance of further spread was more effective.
• COVID-19 spreads via the respiratory route, It's worthwhile to understand the surprising mechanics: 
• As an infected person exhales, talks, sneezes, or coughs, they are ejecting numerous small liquid droplets into the air, which contain innumerable virus particles. Most of the droplets are imperceptible. Infection can occur by inhalation, but more commonly occurs by the droplets landing on object surfaces including skin, where these remain infectious for hours or days, depending on the surface material. Other people can contaminate their hands by touching the affected surface, and then in turn contaminate additional distant surfaces such as elevator buttons, eventually infecting themselves by transporting the virus on their hands to the their mouth, eyes or nose.
• Larger droplets quickly fall onto nearby surfaces, but smaller aerosols can stay airborne for somewhat longer. These smaller air-borne droplets quickly evaporate some or all of their liquid especially in dry climates or due to indoor heating, and thus become even smaller, worsening the problem by further increasing the time that these can stay afloat, and enabling these to be carried by air currents for longer distances. Evaporation may cause the particles to become too small to be reliably stopped and filtered out by other people's masks. COVID can go airborne, since studies have found viral contamination in ventilation systems.
• Shouting, singing, sneezing, or medical intubation seem to increase the production of the smaller variety of droplets, and thus increase risks of airborne transmission, which also anecdotally tends to produce more severe symptoms among those who are infected this way, especially health-care workers. Generally, inhaled particles that are relatively large tend to be trapped and deposited in the nose or trachea, while very small droplets are deposited directly into the lungs. It is unknown if this is the reason why health-care workers tend to experience more severe form of disease, and other plausible causes include: 
• Propensity for infection with smaller droplets arising from aerosolizing procedures such as intubations, which due to small droplet size, may initially be deposited into the lungs rather than nasopharynx and upper airways.
• Infective doses consisting of very high number of virus particles arising from sick patients, a situation which may be unusual for infections occurring outside of a hospital.
• Propensity for an initial infection with a worse strain of COVID-19 that causes severe disease, since it has already caused the patients to be severely sick, and caused them to bring this strain to the hospital or intensive care units before infecting the health-care workers. Milder strains may be more common in cases of the community-acquired COVID-19 infections, outside of hospitals. COVID-19 has already mutated into multiple strains, some of which have been identified, and some of which appear to be indeed more virulent than others. Similar to the strains of Spanish Flu of 1918 with caused 2nd and 3rd waves, natural selection would indeed favor two different viral strains, each tailored for two different niches of transmission: 
1. A mild strain that tends to excel at spreading through the communities would be more effective if those who are infected are asymptomatic or minimally symptomatic, so that they continue to go about their daily routine, and thus infect numerous other people at their typical workplace or school. 
2. A strain causing more severe disease would excel at causing most of those infected to be transported to a new and previously inaccessible area, the hospital, where it can infect the medical staff and eventually their families and other patients. As the continued community spread of the milder strain eventually becomes impeded by many in the community having already been infected and thus having acquired immunity to it, the situation may then favor spread of the more severe strains, as has happened in the 2nd and 3rd waves of the Spanish Flu.
• Approximately 18% of people who are infected never develop any symptoms, and at least some of these seem to be infecting others. Additionally, many people who do develop symptoms are infectious before their symptoms start. There is no practical way to detect them. The only way to ensure that infected people who are asymptomatic wear a mask is to have everyone wear masks.
• If everyone wears masks, this results is two barriers to transmission: One mask on the infected person, and one on the receiving person. Additional barriers should be social distancing, zealous hand-washing and diligent disinfection of surfaces. Even if we assume each of those barriers reduces the chance of transmission only by a mere 50%, then the combined result of 3 such measures in series would be approximately by 50% x 50% x 50%, or 1/8th of the original chance of transmission. The basic reproductive number, R0 is the average number of new infections caused by each infected person. For COVID, this was approximately 2.5 in Wuhan China, and 15 on a cruise ship. If R0 is through this effort reduced to below 1, such as by applying masks to infected persons, masks to receiving persons, and social distancing, this results in R0 of 2.5 / 8 = 0.31, causing the epidemic to fade away: 100 infected people will cause 31 new infections, who will then cause 10 infections, then 3, then 1, then 0. Even if the 50% reduction per barrier is too optimistic, and instead the true value is closer to 25% reduction per barrier, this would still accomplish reduction in the overall chance of transmission and R0 to 1.05, substantially slowing the spread and reducing the number of individuals who ultimately become infected, and reducing the number of patients who will die due to the hospitals being overwhelmed during the peak of this epidemic. Masks would both slow the epidemic and decrease the number of people infected, and allow a reasonable amount of time to develop a vaccine. 

1. Important benefits of an infected person wearing a mask, even if asymptomatic and undetected: 
• Large fraction of the ejected liquids and droplets will be trapped by the mask, and thus not end up in air or on nearby surfaces. The largest visible drops contain the most virus particles, but are easiest to catch by any mask, even a low-quality cloth. Without a mask, these large drops would otherwise fall onto nearby surfaces and cause intense contamination of people's hands when touched; those people in turn are likely to both spread this contamination onto additional distant surfaces, and can also get infected themselves by touching their mouth, nose, or eyes.
• Many of the droplets that are smaller than the mask pores will still impact and adhere to the mask fibers. Imagine throwing water-balloons through a canopy of a tree or through a patch of bamboo forest; while each balloon is smaller than the spacing between the branches, many of the water-balloons would hit the branches and would be stopped, especially if several layers of fibers or branches are in the way. For small particle sizes, electrostatic attraction to mask fibers may play a significant role, additionally trapping them. Although far from perfect, these effects could further reduce the number of droplets and virus particles transmitted to the environment, ultimately reducing the chance of infecting other people.
• Ejected droplets are denser and more massive than the surrounding air, resulting in a higher momentum and more linear trajectories than the air; the droplets are more likely to impact mask material, while the air is able to flow around fibers or obstacles, such as around the edges of the mask.
• Droplets are largest during ejection, and thus easiest to capture at that time. After a brief period of time traveling through the air, droplet size decreases due to evaporation, especially in dry climates or due to indoor heating, resulting in very small particles that can stay afloat in air for a long period of time and can be carried by air currents through large distances causing prolonged exposure to distant co-workers, and which may also contaminate distant objects or pass through small pores in the recipient's mask.
• Velocity of ejected gas and droplets is substantially reduced by any mask, even one with large pores. This decreases the distance that some the droplets travel before falling.
2. Effects of non-infected recipient wearing a mask:
• The recipient's mask is likely to trap some, even if not all, of the small air-borne droplets. This may in some situations reduce the number of inhaled virus particles to below the minimum infective dose, and prevent infection entirely.
• Some researchers believe that if fewer virus particles are introduced initially, this may result in milder symptoms or better chance of survival in some viral infections, since this would give the immune system slightly more time to start developing antibodies and immunity while the virus replicates within the body before it reaches similar numbers that a larger infective dose would introduce instantly. It is unknown if such an effect is possible with COVID-19. A mild disease would have a beneficial quality similar to a vaccine, causing immunity even to a large infective dose in the future.
• Mask may deter the wearer from touching their nose or mouth, thus reducing the risk of this route of infection.
• Valuable psychological effects on others: the wearer sets an example and thus encourages multiple other people to also wear masks, likely causing others to take the pandemic more seriously, presumably also improving the efforts of some observers at social-distancing, hand hygiene and surface disinfection. Some of these observers may already be unknowingly infected or may become inadvertently infected later, at which point they would convert to the first case of an infected person wearing a mask and materialize those benefits. This psychological effect on multiple other people may plausibly have a larger impact in reducing R0 than the physical protection provided by a single mask to one individual, as these other people may in turn adopt and further spread similar behaviors, in a fashion reminiscent of a viral spread.
• Poor quality masks are wonderful, even if they let half the viruses through. Not because they guarantee the prevention of transmission to a single individual, but if worn by everybody, these collectively substantially chip away at COVID's R0 within the population, and in conjunction with social distancing, hand-washing, surface disinfection have the power to make COVID go extinct. This collective effect in turn would be more effective than the finest N95 or P100 mask on any one individual within a society where COVID-19 is rampant. Of course, people who are likely to interact with COVID-19 carriers or patients today, should wear high-quality respirators and other protections.
• Increased mask-wearing, even if partially effective and not practiced by everyone, could shorten a prolonged shut-down of economy, and decrease the associated enormous daily costs.
• In USA, the CDC recommended that infected persons wear masks. However, the CDC and Surgeon General did not recommend that everyone wears masks in public. This is illogical if many COVID patients don't know that they are infected yet. CDC's recommendations were motivated by the logical and real reason of shortage of masks in the USA, and concerns that if everyone buys masks, these will not be available to health-care personnel, who need masks the most. Using masks too-early in the epidemic would also consume numerous masks at a time when majority of people were very unlikely to encounter anyone who is infected. However, that time has now passed. Persisting in those recommendation causes a profoundly suboptimal situation. Masks and other personal protective equipment are sadly often unavailable to health-care personnel today. The proper way to address the mask shortage is to drastically increase the production of masks and hand sanitizers and ration them to individuals, not to hospital corporations or government agencies, as to prevent hoarding in stockpiles and price gauging. If needed, the Defense Production Act, Presidential Executive Orders, or state-level enforcement could be invoked, to produce numerous masks and to encourage or mandate the public to use these. If masks and hand-sanitizers are easily available in South Korea and China at convenience stores, why is this impossible in USA? Even improvised low-quality masks or bandanas might be substantially helpful, for the reasons described above. Government and ordinary citizens should vigorously encourage public to use masks in conjunction with hand-sanitizers, social distancing and the economy-wrecking lock-downs. Citizens need to be proactive, as we cannot depend on the government to provide competent crisis management, as has happened before during Hurricane Katrina response, wherein FEMA bureaucracy resulted in electrical generators being stockpiled and withed from hospitals, volunteers being deterred by bureaucracy and unable to help, and ice shipments misdirected to wrong states.
• Current shortage of masks, sanitizers, and Protective Personal Equipment (PPE) results in the actual people and health-care workers at the front-lines not having these today for situations in which PPE should be used, resulting in spread of the infection to health-care workers and other patients. This shortage crisis is caused by: 

• Requirements for masks and other PPE to be NIOSH-approved. However, this approval process is crippled by bureaucracy, and NIOSH is currently unable to communicate with or approve companies that are eager and able to manufacture high-quality masks, but today cannot.
• Various entities are stockpiling PPE as "preparation", such as Federal government, state governments, and hospital corporations, and to a lesser extent individuals, thus rendering these unavailable to healthcare workers and other individuals.
• Supply chains of masks and materials were interrupted, some of which were manufactured in China.
• World-wide spike in demand.
• Physicians throughout USA are complaining that the hospitals hoard the masks and deny masks to the physicians unless the patient is already confirmed have COVID at which point the physician is likely to have already become infected. This is because the hospital is anticipating a mask shortage during increased number of cases in the near future. Today, this results in increased infections among health-care workers, and in turn increased spread to patients who are seeking medical help for other reasons. Some appalling attempts to deal with the shortage included a lobbying effort by a Hospital Association to remove OSHA requirements of providing protective equipment to physicians and other health-care workers, as to reduce liability to hospital corporations.
• Measures that work on population-scale can indeed be very effective, even despite small subgroups that are non-compliant. However, such irresponsible persons and groups do cause significant damage and mortality by noncompliance, typically those who are young or carefree types. Part of the prevention effort should vigorously focus on appealing to such individuals through social media, celebrities and their communities. Additional measures that other countries discovered were necessary included strictly-enforced quarantines at dedicated facilities separate from patients' families and neighbors, and disinfection of densely-populated public areas.

Further Reading and References

1. Are administrators disciplining doctors who wear masks too often? by Mia Marietta, MD - American Hospital Association has submitted a plea to Nancy Pelosi to have OSHA withdraw workplace safety standards. 
2. Why the Second Wave of the 1918 Spanish Flu was so Deadly
3. FEMA Mistdirected shipments of ice to wrong states.
4. Compounding Disaster with Disaster by Russell S. Sobel and Peter T. Leeson: FEMA bureaucracy resulted in electrical generators being stockpiled and withed from hospitals, volunteers being deterred by bureaucracy and unable to help.
5. Interview with South Korean Infectious disease specialist, Professor Kim Woo-joo from Korea University Guro Hospital
6. Lesson from South Korea on how to slow the COVID-19 spread | ABC News
7. The Size of the Viral Inoculum Contributes to the Outcome of Hepatitis B Virus Infection by Shinichi Asabe, Stefan F. Wieland, Pratip K. Chattopadhyay, Mario Roederer, Ronald E. Engle, Robert H. Purcell, Francis V. Chisari
8. Hospitals Tell Doctors They’ll Be Fired If They Speak Out About Lack of Gear By Olivia Carville, Emma Court, and Kristen V Brown