Vaccines

 I keep hearing people say that the COVID vaccine should prevent the disease. Words mean something. Prevent means what? Symptoms, carrier status, or just what.

Vaccines work by activating the adaptive immune system, B cells and antibodies and some T cells. One can still get infected and be a carrier after being vaccinated. Vaccines create antibodies that fight the disease when infected. Depending on your immune system you may get sick or not. You are still infected. Vaccines do NOT prevent infection. They mediate it when infected.

Given our grossly incompetent educational system we seem top spend more time on one's sexual proclivities than on basic biological facts. Pity.

Fighting the Last War

 The vaccine approach is to use the mRNA sequence for the spike protein on the initial viral sequence. Along comes the Delta variant. We know the details of that variant, namely the mRNA of its spike. It differs a bit. BUT, instead of adding this mRNA to the vaccines to combat COVID head on we are relying on the original spike to hopefully keep us safe! 

This is akin to fighting the last war. The spikes will be changing continuously but we are more than six months in and no progress. Axios has noted:

In a statement, Pfizer said it and BioNTech "expect to be able to develop and produce a tailor-made vaccine against that variant in approximately 100 days after a decision to do so, subject to regulatory approval."

 So what is holding you up. Well first the original vaccines needs FDA approval. Perhaps we can get help from the Taliban in how to move quickly? The FDA seems constipated on the original approval. Second, like flu vaccines, a new mRNA, with six nucleotide changes, out of 3,000, gets us there. It is a 20 min labe exercise for a college Junior. I suspect we can treat this virus as we do flu viruses with annual boosters tracking the ever changing variants. 

The issues is that no one is talking about this amongst the herd of experts in DC. Pity!

Aerosols, Masks, and the CDC

 My grandmother was the Head Nurse at Seaview Hospital in New York City during the TB and Influenza outbreaks from 1910 through 1930. She lived well past 90 and I never remember her sick a day. She wore a mask.

Then again a hundred years ago medicine was a bit different. New York had a Public Health system but millions of immigrants. People and troops were coming and going and needless to say the understanding of viruses was nil. Yet by late 1920 things returned to normal. Masks were accepted as a medical necessity, nothing else was available, and they were not politicized.

Now 100 years later they seem to be the focal point of political intrigue. The CDC has a "mask" web site that allegedly lays out the "science". They note:

Multi-layer cloth masks block release of exhaled respiratory particles into the environment,along with the microorganisms these particles carry. Cloth masks not only effectively block most large droplets (i.e., 20-30 microns and larger)but they can also block the exhalation of fine droplets and particles (also often referred to as aerosols) smaller than 10 microns ;which increase in number with the volume of speechand specific types of phonation. Multi-layer cloth masks can both block up to 50-70% of these fine droplets and particle  and limit the forward spread of those that are not captured. Upwards of 80% blockage has been achieved in human experiments that have measured blocking of all respiratory droplets,⁴ with cloth masks in some studies performing on par with surgical masks as barriers for  

Now the real problem is not the mask but the aerosol transmission. Here are some as of yet unanswered questions:

1. In an infected person, we know that the virus replicates in the cells and that the cells exude virions which can be set free when the infected person breaths out. What does the vehicle of the expirated virion look like? Is it a hydrogen bonded water sphere with the virion inside, or something else. How large is this expelled aerosol and how many virions are in it?

2. We know the virus replicates at 98F in the lungs and seems dormant at 94F in the nasophyranx. We think. Now in a vaccinated person, we also know that if the immune system is properly functioning that virions that make it to the lung are attack and neutralized. Is this the same with the dormant nasopharynx virions? If no then is the nasopharynx virions the transmission agents,

3. If aerosols are the dominant means of transmission, and if the aerosol particles containing virions are the transmission elements, and if these aerosols are say 100 nm, 0.1 micros, we know from Stokes law that they just hang in the air for a real long time. Is this the real cause for transmission? If so six feet is useless. Masks may help, but immunization is the only answer.

4. It appears that despite the now substantial research that little has been done on real viral transmission. We see people singing, droplets flying about, but the aerosol effects almost disregarded at the small nm level.

 Understanding how the virus is transmitted is in my  mind the number one question now and in the future. I also would not totally negate surface infections. Yet.

What is an Aerosol?

 There is a fantastic piece in Wired discussing the understanding of aerosols and the transmission of the corona virus. It notes:

On the video call, tensions rose. At one point, Lidia Morawska, a revered atmospheric physicist who had arranged the meeting, tried to explain how far infectious particles of different sizes could potentially travel. One of the WHO experts abruptly cut her off, telling her she was wrong, Marr recalls. His rudeness shocked her. “You just don’t argue with Lidia about physics,” she says. Morawska had spent more than two decades advising a different branch of the WHO on the impacts of air pollution. When it came to flecks of soot and ash belched out by smokestacks and tailpipes, the organization readily accepted the physics she was describing—that particles of many sizes can hang aloft, travel far, and be inhaled. Now, though, the WHO’s advisers seemed to be saying those same laws didn’t apply to virus-laced respiratory particles. To them, the word airborne only applied to particles smaller than 5 microns. Trapped in their group-specific jargon, the two camps on Zoom literally couldn’t understand one another.

The real issue is that one must define an aerosol. There is a classic book by Hinds, Aerosol Technology (Wiley, 1982) worth reading. In the introduction the author notes:

The microscopic particles that float in the air are of many kinds; suspended solid particles, smoke from power generation, photochemically formed particles, salt particles formed from ocean spray, and atmospheric clouds of water droplets or ice particles....These airborne particles are all examples of aerosols.

The author continues to give examples and counter examples. But in the Wired piece one sees that the corona virus is carrier from person to person by aerosols. The questions are:

1. What is the structure of that aerosol?

2. What are its dimensions?

3. What are its aerodynamics?

4. How does it go from one person to another?

5. How is it generated in an infected person?

6. What are the dynamics of aerosol bursts?

And the list goes on. The article does not answer any of these questions. What we do know is that the virion is about 30 nm in diameter and that it may be transported in an aerosol of water about 100 nm in diameter. These small aerosols may collide and get larger or smaller, they may gather as a quasi cloud, they may do lots of things.

But we know that a particle such as this will fall according to Newtons law of gravity with a force of mg, mass times the gravitation pull. Yet against that may be a hydrostatic force due to a differing air temperature in the aerosol and drag due to the viscosity of air. This is the grossly simplistic model.

F(viscosity)=3πμVd

 where we have the viscosity, velocity and diameter. In a simple single particle case the terminal velocity, the settling velocity is:

V_TS=(αd²g)/(18μ)

where we first see the density of the particle. Simplified we have for small particles:

V_TS=0.003d² (cm/sec) d in microns

Now this is quite slow. One must realize the particle has a horizontal component that starts high and it too gets to a terminal state. Thus small particles can get stuck in the viscous air. 

Now the fun begins.

1. The particles have lots of sizes.

2. Brownian motion occurs

3. The aerosols collide, get bigger or smaller or evaporate totally

4. There are electrostatic effects

5. and so forth!

The article concludes:

In early May, the CDC made similar changes to its Covid-19 guidance, now placing the inhalation of aerosols at the top of its list of how the disease spreads. Again though, no news conference, no press release.

The problem is that this is a really hard problem. At best we can say that "aerosols", whatever they are, spread the virus. We can also say that the CDC and WHO have not only been clueless but reckless in their approaches. We can make models, but if this pandemic has taught us anything it is that models have been not only useless but counter-productive. We are still at the stage of defining the issue. That takes measurements, data flow, monitoring, and the things we have been doing for a century. 

Regrettably we have seen the worst of politics and "science" in the past year, and its intensification most recently. It is clear to me that the CDC has lost any credibility. Yet we need researchers who can tackle the issue. The Wired piece shows one such alternative. I am sure there are many more.

Also I believe, and this is a belief, that aerosols of the corona virus do linger, but the question is; for how long are they viable. RNA is very fragile, it decays and breaks down, especially single stranded. The aerosol can protect it but for how long. That is just another of the possibly hundreds of questions. We need data, not equations. They may come later, possibly.