Emergence of a Deadly Coronavirus

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Aerosol Transmission

When people exhale, they expel respiratory droplets with a wide range of sizes. Most are smaller than 10 microns in diameter. These can quickly decrease to approximately 40% of their original diameter, or smaller, due to evaporation.

The droplets will not completely evaporate, however. This is because they consist of both water and organic matter, potentially including the SARS-CoV-2 virus. These tiny droplets stay suspended in the air for minutes to hours, posing a risk to anyone who comes into contact with them. When suspended in the air, these droplets are commonly referred to as aerosols.



Cigarette smoke comprises particles that are similar in size to the smaller respiratory droplets expelled by humans – the ones that linger in the air the longest. While it’s not a perfect analogy, picturing how cigarette smoke moves through different environments, both indoors and outdoors, can help in visualizing how virus-laden droplets circulate in the air.

Outdoors, the combination of physical distancing and face coverings provides excellent protection against virus transmission. Think again of being near a smoker. Smoke can be carried by the wind much farther than 6 feet, but high concentrations of smoke do not usually build up outdoors because the smoke is quickly diluted by the large volume of air. A highly effective strategy to avoid breathing smoke is to avoid being directly downwind of the smoker. This is also true for respiratory droplets.

Indoors, the picture is very different. Very light room air currents from fans and ventilation units can transport respiratory droplets over distances much greater than 6 feet. However, unlike being outdoors, most indoor spaces have poor ventilation. That allows the concentration of small airborne respiratory droplets to build up over time, reaching all corners of a room. There is no safe distance in a poorly ventilated room, unfortunately.

Source: What a smoky bar can teach us about the ’6-foot rule’ during the COVID-19 pandemic

I feel very safe outdoors because the city I stay in is very windy and anything in the air will be dispersed very rapidly. Thus I don't wear masks in the outdoors.

Are the Greyhounds and other long distance coaches safe? They showed in a video how they sanitize everything from top to bottom before the bus leaves the depot. I am thinking of visiting a friend in a distant city next month, which is an overnight trip. Will take hand sanitizer along - preferably alcohol based and perhaps take a few extra vitamins, and minerals such as zinc.

I wear my buff to the stores as per the government rules, but don't like to hang around in the shop or mall too long breathing in my CO2 so tend to get what I need quickly and get out.

Another reason not to smoke

^Thanks, Jimmy. I understand they will take temperatures prior to anyone boarding and not allowing any passenger to board if the person has a higher than normal one. I also thought of taking some or other alcohol solution as long as they don't think I've been on a heavy drinking binge!

I know you're always interested in information, so South Africa's statistics as of now stand at around 648 000 total tested positive, 576 000 recoveries and 15 427 deaths.

Israeli government to impose second Covid-19 national lockdown

^A complete overreaction on the part of Netanyahu.

5 km can be considered a reasonable limit. Not 500m.

I knew there was some use for my giant chopsticks

I do like those chopsticks.

Scientists at the University of Pittsburgh School of Medicine have isolated “the smallest biological molecule” that “completely and specifically neutralizes” the virus that causes coronavirus.

The antibody component is 10 times smaller than a full-sized antibody, and has been used to create the drug Ab8, shared in the report published by the researchers in the journal Cell on Monday. The drug is seen as a potential preventative against SARS-CoV-2.



According to the report, the drug has been “highly effective in preventing and treating” the SARS-CoV-2 infections in mice and hamsters during tests. The drug also reportedly does not bind to human cells, which suggests it will not have negative side-effects in people.

“Ab8 not only has potential as therapy for COVID-19, but it also could be used to keep people from getting SARS-CoV-2 infections,” said co-author John Mellors, chief of the Division of Infectious Diseases at Pitt and UPMC. “Antibodies of larger size have worked against other infectious diseases and have been well tolerated, giving us hope that it could be an effective treatment for patients with COVID-19 and for protection of those who have never had the infection and are not immune.”

Researchers are also “thinking outside the box” for how the drug could be administered, stating it may be able to be inhaled or through a superficial injection, instead of an IV.

According to the report, the team at University of Texas Medical Branch Center for Biodefense and Emerging Diseases and Galveston National Laboratory tested Ab8 and found it blocked the virus from entering cells. In mice trials, those treated with Ab8 had 10-fold less of the amount of infectious virus compared to those that were untreated.

Source: University of Pittsburgh scientists discover antibody that 'neutralizes' virus that causes coronavirus

I had a chat with a kitchen countertop installer yesterday. We were discussing COVID. He said there currently is a run on toilet paper again. There are probably people preparing for the second wave. So you know the drill by now. If there is something that you found difficult to buy because it was out of stock during the first wave, it would be prudent to buy some now in preparation, just in case.

Note to myself: Buy some more Pizza, Campbell's Beefy Mushroom soup, Chicken Rice-A-Roni, more hamburger meat, paper towels, etc.

He also said that many people during the first wave bought bidet toilet seats. I guess that is one way to solve the toilet paper shortage.

THAT is one of the most intelligent ideas/suggestions I have heard yet!

Aerosol Transmission

As many countries have started to relax their respective lockdowns, some agencies, companies and facilities are beginning to turn a blind eye to a big concern: Can the novel coronavirus be transmitted through the air?

A major reason for this relaxed attitude is the absence of scientific consensus between two contending groups on the matter of aerosol transmission. One group says the virus is transmitted through mucous droplets exhaled by infected humans, and which fall down within a short distance (so the 2 m ‘safe distance’ rules). The other group claims the virus is viable even in much smaller droplets, known as aerosols, that can stay afloat for longer and travel larger distances.

These opposing viewpoints are often presented in the press in an oversimplified way, without the requisite nuance.

In this debate, as it stands, we know the following:

1. The virus can’t propel itself

2. The virus is inside mucous droplets exhaled by people, and the virus’s ‘range’ depends on how far these droplets can travel

3. How far these droplets can travel depends on conditions like air movement, humidity, ventilation and whether one is indoors or outdoors

4. The best way to avoid these droplets is to: i) ventilate your room as much as possible; ii) maintain a safe distance from people; and iii) wear a mask.

Based on what we know of other respiratory viruses, we expect the one that causes COVID-19 to have three main modes of transmission – close contact (droplets), fomites (touch surfaces) and airborne transmission.

Since the COVID-19 outbreak first began, the WHO has highlighted the first two modes but didn’t pay much attention to the third.

Now, why are scientists divided over something seemingly so simple? A part of the answer lies with labels and the history of medicine.

When we breathe, talk, cough, or sneeze, we exhale many small and large fluid particles. Most of them are 1-10 microns wide. (A human hair is between 50-80 microns wide.) Some droplets are larger as well – even as big as 1 mm. You might have noticed flecks of saliva escape people’s mouths when they’re talking. But these are rarer.

For historical reasons, epidemiologists and aerosol scientists have evolved different definitions of ‘droplet’ and ‘aerosol’, giving rise to confusion about what these terms refer to today among different experts. However, the epidemiologists’ definition is more outdated, and leads to problems in risk communications and in agreeing on the transmission modes of various diseases.

A particle of size 5 microns is too small to see with the naked eye. But if you’ve ever dusted your room with sunlight streaming in through a window, you might have noticed these particles floating around for a long time, and over a relatively large distance. According to a standard reference for aerosol engineers, a 50-micron particle can stay afloat in still air. And the volume of a 50-micron particle is 1,000-times larger than that of a 5-micron particle.

The World Health Organization (WHO) took a few weeks to begin recommending that everyone wear masks as a preventive measure. Now, however, both the WHO and the U.S. Centres for Disease Control recommend the use of masks – but neither considers aerosol transmission to be likely. It took an unusually public outcry from over 200 experts for WHO to admit that aerosol transmission was even possible. One reason could be that the organisations didn’t wish to create panic. But from the authors’ point of view, it could be a healthy dose of panic to counteract the complacency among companies and governments as the latter proceeds to relax lockdowns.

One thing we must remember is this: the virus does not understand or follow our definitions. With reputed infectious disease experts like Dr Antony Fauci acknowledging the possibility of aerosolised transmission, we hope that progress towards a consensus will be quick. So while scientists work to determine the significance of aerosol transmission during the coronavirus pandemic, we must assume in the interest of safety that aerosol transmission is possible and viable.

Source: Aerosol Transmission of COVID-19 Virus: What Is, and Isn’t, up for Debate