COVID-19 and UV air cleaners
A renowned scientist and intensivist, Dr. Paul Marik, Chief of the Pulmonary Department of Eastern Virginia Medical School in Norfolk, made a video presentation on COVID as part of Science Day.
“COVID is not a flu. We are all in really big trouble. As of yesterday there were seventy new cases of COVID and it looks like the graph is going up. So we are in for a bad winter.”
When huge amounts of conflicting information flood the Internet and the media, a report from an acknowledged practitioner is exactly what we need in order to successfully combat the pandemic that has swept over us.So, let us dwell on the issue of human infection with coronavirus and consider what Dr. Marik said in more detail.
The main way of spreading SARS-CoV-2 is aerogenic transmission with pathogens localized in the mucous membrane in a respiratory tract of an infected organism and transferred to a new victim through the air. This mechanism of infection transmission is defined by spreading through airborne droplets and airborne dust. With airborne transmission, the virus enters the air when coughing, sneezing, etc., stays there in the form of an aerosol and is introduced into the human body by inhaling the contaminated air. With the air-dust route of infection, the coronavirus enters a person through dust particles (if SARS-CoV-2 remains for a long time in the external environment, as stated by researchers of the Australian Centre for Disease Preparedness: “... at room temperature, the coronavirus can persist up to 28 days").
Dr. Marik downplays other types of infection like those acquired by surface contact. We can agree with this for another reason: according to Dutch scientists from the Habrecht Institute, Erasmus University Medical Center of Rotterdam and Maastricht University, a similar infection acquired by contact affects human intestinal cell cultures, and, in patients with coronavirus is expressed in such symptoms, like nausea and diarrhea, which is different from the symptoms of the pulmonary form of COVID spread aerogenically.
Let's focus our attention on a process of aerogenic infection. When breathing, an infected person throws out up to a million viral particles (virions) with each exhalation. With the inhaled air the virus enters the nasopharynx of a random victim, and there, it rapidly replicates due to the ability of SARS-CoV-2 to suppress the immunity.
Thus, the most rapid viral replication with increasing viral load occurs in the nasopharynx. Then, the virus enters the lungs by aspiration.
Those infected with COVID are the most infectious during the incubation period before symptoms appear, but their virulence reduces in the early days of symptoms. This is the main danger of the virus, since due to the huge viral load of pre-symptomatic people, it is the most infectious in asymptomatic carriers, or, simply put, those who are not aware of their illness are the most infectious. Viral replication in the nasopharynx reaches its peak before the onset of symptoms, and a huge amount of viral aerosol is released into the air. If this occurs in closed rooms and, which is especially dangerous, in those equipped with closed heating and/or air conditioning systems (without ventilation), the concentration of viral aerosol increases, thus, any visitor is guaranteed to be infected, even if the host left the room a few days ago.
When dealing with contacts in open or well-ventilated areas, the most effective way to combat COVID is using face masks. Obligatory for everyone. Masks protect both ourselves and others. By wearing a mask, an infected person reduces the speed of exhaled air, which prevents the virus spread by minimizing the affected area, and, at the same time, reduces the amount of viruses that an uninfected person inhales. In this case, you should know that the mask is able to retain large particles, such as drops and dust, containing a viral infection. The spreading of SARS-CoV-2 virus itself, measuring 0.1-0.125 microns, can not be stopped by any of the existing face masks in the world.
A frequent ventilation is mandatory for premises, as well as a disinfection of surfaces, an efficient ventilation (without a recirculation mode), and the use of active air disinfectants and powerful models of recirculators in overcrowded areas.
The most important point: the severity of the airborne disease (the depth of the lung damage) depends on the concentration of the viral aerosol and the volume received by an infected victim, or, speaking in non-scientific terms, those who inhaled less virions had a milder form of illness or suffered it asymptomatically.
Protect yourself - prevent effectively the accumulation of microorganisms in the air of your premises, to reduce the risks of surface contamination, infection of the inhabitants and the visitors, the spread of microorganisms to other premises, and the like.
© Oleg Osadchuk