Tag Archives: Dr. C Opinions

Covid-19 Review: Airborne Transmission Of Viruses

In a very good article, the Journal ‘Science’ has collated a lot of basic science regarding aerosol transmissions in viral infection generally, and Covid-19 in particular.

Click here to read article in Science Magazine

Early in the epidemic, I thought that large droplet transmission, which fell to the floor, and was transmitted by fomites and hand autoinoculation into the respiratory membranes, was more important. The main thesis of the article is that it is not large droplets, but aerosol particles that mainly transmit.


The secondary assertion is that aerosols can be up to 100 µm microns in diameter and still be transmitted by inhalation. they also stated that particle size of equal or less than 5 µm contain more virus particles than all the larger particles put together in spite of the greater mass of the larger particles . Normal speaking creates about 1000 aerosol particles per minute, And normal breathing about 7200 aerosol particles per liter of exhaled  air. Coughing is more sporadic and tends to produce the larger droplets which don’t stay airborne as long, but I wouldn’t count on it.  

There is a tremendous difference between individuals as to the number of particles they generate. It’s estimated that 10 to 20% of individuals account for 80 to 90% of the virus.

Slide number two  deals with viral load and infectivity which is a function of the pH value, electrical charge, and other characteristics of the virus. An important point is that even though there is lots of viral RNA, that doesn’t mean that the virus is infective. Once again there’s a tremendous difference between the infective viable virus content of the aerosols from infected patient to patient. He stated that in one room with two Covid patients, they were 6 to 74 TCID/50 per liter, which means you’re almost certain to be infected if you don’t have a mask that filters out the virus, or some kind of purification in the room.

Slide Three was very interesting to me. The persistence  in hours graphed against the aerosol particles size. 100 µm particles stay in the air only about five seconds, 5 µm particles stay in the air for 30 minutes, and one micrometer particles will stay in the air for 12 hours or more.

The fourth slide talks about factors affecting the distribution of indoor aerosols. There may be certain parts of the room where the particles congregate , depending on the ventilation type, whether natural, mechanical or filtered, flow patterns within the room, and indoor filtration and killing devices such as ultraviolet light.

Mention is made of the CO2 level in the room as a measure of air circulation. There is a higher CO2 in the air with lots of people and poor ventilation. The recommendation is that 7-8 ppm is about the highest acceptable level, and the possibility of using a portable HEPA filter would not be a bad idea for people frequenting indoor restaurants. Of course, outdoor air with its breezes, dispersion, less humidity, higher ultraviolet and usually Greater dispersion of people is preferable to indoor contact.

Some other interesting points are that children produce less aerosol particles because they have a smaller number of bronchi. I thought the bacteria were less likely to be aerosol transmitted than viruses, but they state that the R0 of tuberculosis can be as high as 4.3, vs. 7-8 for covid. The typical tuberculosis bacillus is relatively large, and yet is only 2 µm in length, well within the size of an aerosol particle.

–Dr. C

Doctor’s Journal: ‘Alcohol And Health’

Alcohol has been used by mankind since before recorded history. It causes a pleasant slowdown of the nervous system, Lessening inhibition  and loosening the tongue, making it the perfect lubricant for social interaction. Unfortunately, it is a metabolic poison.

Excess alcohol use is common enough to have resulted in its prohibition in the United States in the 20s. The side effects of this prohibition proved worse than its benefits, and alcohol currently enjoys the status of one of the few legally permitted Psychoactive drugs.

After diligently searching for beneficial effects of alcohol, society discovered that mild drinking promotes longevity. It is difficult to drink just the right amount of alcohol, and  There is little doubt that excessive drinking is deleterious to the body.

The liver is the organ responsible for getting rid of alcohol. Unfortunately, liver function gradually declines with age, so that the older you get the less alcohol you can tolerate. 14 drinks a week is the suggested upper limits for alcohol’s benefit, and this number shrinks as you get older.

I became interested in alcohol in the elderly because of a friend whose doctor discovered that his red blood cells were enlarged. This can be due to alcohol in at least two different ways. If you drink too much alcohol, you need less calories, and often have a poor diet as a result. B12 (and folic acid) deficiency can result and may cause large red blood cells.

I also learned that alcohol can directly caused large red blood cells because of the toxic effects on the bone marrow, where Red blood cells are made. The very young also have more difficulty with alcohol. Early in my career I discovered 2 young infants who had convulsions after getting into their parents wine closets. These convulsions turned out to be caused by a low blood sugar which developed because glucose, the common blood sugar, is consumed in the process of burning, or metabolizing, alcohol.

My own use of alcohol has been progressively declining with age. I feel good with less alcohol for a shorter time the older I get.

—Dr. C.

THE TWO SIDES OF STRESS

Stress in modern times most often has a BAD connotation. Stress is blamed for a raft of disorders from headaches to cardiovascular disease. Indeed, stress activates the adrenocortical “alarm reaction”, and if unremitting can indeed implement many chronic problems.

ACUTE stress, however, is often beneficial. The body responds favorably to measured amounts of brief stress, especially if it is YOUR CHOICE, and not demanded of you. It is WORK, when you would rather be doing something else. It is FUN when you are hiking up a steep but beautiful trail in the Swiss Alps. The flavor of reality takes place in the mind.

HEAT SHOCK PROTEINS (HSP) illustrates how your body works. If you get a little overheated, HSPs are produced and benefit any misfolded proteins that result. If you go hungry, a metabolic pathway burns fat and increases insulin sensitivity. If you exercise your mind, BDNF and new neurons result.

THE BODY ADJUSTS TO THE DEMANDS, and benefits flow. The body is designed to function. The trouble is that placing demands on the body is effortful, and effort requires discipline. The Paleolithic Hunter-gatherer lifestyle, the reality to which our metabolism is attuned, REQUIRED plenty of aerobic exercise, just to get food and avoid harm.

Our modern life is replete with deadlines and requirements, and hearts beat rapidly from ANXIETY rather than aerobic demand. Even the trades, which used to require physical energy expenditure have a lot of labor-saving devices. Children, insead of running, ride around on electrically propelled scooters. Little wonder that people are “out of shape” and gaining weight.

–Dr. C