Article 1: Common Causes of Transmissions of COVID-19

Sunil J. Wimalawansa, MD, PhD, MBA, DSc.

What is COVID-19?

COVID-19 is an RNA virus belongs to coronavirus family that is a highly infectious.  It is 20-time more infectious than SARS and MERS but 10 to 15 times less deadly than these two coronaviruses.  This virus has a higher degree of morbidity and mortality than ordinary flu viruses. There are hundreds of coronaviruses that are associated with wild animals.  The latter is the reservoir for coronavirus, generally do not slay animals. Contrary to believes, it predominantly spreads via aerosols (inhalation) and also through droplets getting into the body through inhalation, mucous membrane, and gastrointestinal tract.  

The current pandemic:

The situation with the global COVID-19 pandemic is unprecedented.  Because of the rapidity of the spread, millions of people got affected within a three months period.  However, this is no comparison with the Ebola epidemic that kills those who gets infected. Considering the mortality rates are relatively low, between 0.5 and 3.2%, it still needed taking strategic actions to bring it under control.  However, that does not include locking down provinces, states or a country, or imposing curfews. Such drastic actions invariably cause more harm to people than form the virus.  

Despite above, each country took variable actions to control the disease, aiming to control it at the earliest possible.  Leaders of the countries that listen to experienced experts, evaluated the situation properly, explained and educated its public, and took firm and prompt actions, a such as Taiwan, New Zealand, Iceland, South Korea, and Germany were managed to get it under control quickly with minimal harm to the country.  In contrast, those countries took a while to implement prevention programs like Italy, U.K., and USA and those countries ‘think that they are doing well’ yet not taking adequate actions, will continue to have problems.  

This is not the time for “talking heads” of the media, politicians, and the military to speculate and express their politically views or taking actions based on “gut-feelings.” None of these personnel have experience in handling major public health outbreaks like COVID-19.   Decisions and unwise actions taken by them further harm the country, its economy, and citizens. Instead, everyone must be united, and work with respective administrations to control the disease to coming out of the current situation earliest possible. 

Controlling COVID-19:

There is no one measure that can be implemented to achieve the goal of complete control or eradication of the disease.  However, based on misguided assumptions, and unrealistic faulty models, some countries continue to rely on months of curfew with little benefits.  Such manoeuvres alone never will be successful. In major public health crises, one must balance the essential needs of its citizens, such as food, transport, health, and other essential services, versus controlling the microbial invasion.  

Those with strong immunity is affected mildly and some not even know that they had the disease.  Whereas, those with impaired immunity due to any reason can develop a serious manifestation of COVID-19 syndrome.   Because of the impaired immune system, a sector of immune cells that produce inflammation⎯cytokines⎯markedly overreact, causing acute lung, vascular, and organ damage that can cause death. 

Common modes of transmission:

Contrary to the popular believe, the commonest mode of the viral spread is not from large droplets but through inhalation.  Since larger droplets come out from the mouth and the nose of infected persons following coughing are larger than 5 microns in diameter.  Consequently, these do not travel more than a meter.  

The commonest mode of COVID-19 viral spread is through the aerosolized, smaller droplets, that are less than 5 microns⎯transfer of viruses through the air.  Because these bio-aerosols particles are much lighter, these can float in the air in limited spaces for up to, 90 minutes.  This is more than enough to infect dozens of people, who might inhale or even while talking, in the presence of virus contaminated air.  

The only effective way to prevent getting infected is to wear effecting face masks, such as N95 or similar protective face masks.  While larger droplets can carry exceedingly high numbers of viruses, small aerosolized droplets contain less. However, these are enough to infect a number of people, as documented in China and several other countries.  

Smaller droplets suspended in the air is the commonest mode of transmission:

Because larger droplets are heavier than the air, these will stay in the air for only few seconds.  These are pull towards the floor by the gravity and get attached to surfaces. Whereas, in confined spaces, smaller aerosolized forms drift in the air and could infect people who are inhaling such, up to 10 meters (> 30 feet) away.  

Therefore, contrary to the claims by the WHO, in confined air spaces such as a room, these bio-aerosols can easily spread across and infect people.  Such places include but not limited to, any place with human gatherings, such as congregations, parties, classrooms, movie theatres, in buses and aircrafts, for that matter in any room.  

Because of the misguided views disseminated by health authorities including WHO, people continue to blindly accept the myth that staying 2 meters away from an infected person, there is no chance that one could get infected.  This is a false narrative, so as so many others. This resulted in developing over-assurance of authorities and people globally. This over-confidence might be responsible for many of the recent infectious sporadic outbreaks. 

The effect of particle sizes reference to the spread of the disease.

The average diameter of COVID-19 virus is approximately, 0.125 microns.  By definition, HEPA filters can remove any particles with the size, above 0.3 micron, with an efficiency of 99.97%.  Although diameter of an individual COVID-19 virus is smaller (0.125 microns); that is smaller than the pore sizes in HEPA filter membranes.  Despite that, HEPA air filters can remove COVID-19.  

This is because of two reasons; aerosolized droplets are still thousand times bigger than 0.3 microns and the inherent process of diffusion happening across the HEPA filter membranes.  Thus, HEPA filters are capable of capturing smaller particles, including nanoparticles. As a result, HEPA filters can remove virtually all COVID-19 particles from the air. This is why the Federal Aviation Authority (FAA) recently mandated all airlines to install HEPA filters in all passenger aircrafts to minimize the possibility of infecting passengers and the staff.    

The next article will discuss issues related to social distancing and additional that help to controlling COVID-19.