My understanding of the article was that it doesn't need to be a blood-borne disease. The authors point out several times that, while most people would assume this works by directly killing germs (i.e. like sterilizing water with UV), this is not the mechanism. The exact mechanism is still unclear (which is one of the reasons it was never as widely adopted), but it seems more likely to be boosting the immune system.

So there would be no need to shine UV light directly into the lungs.

To expand on the unknown method of action. It could for example be removing other pathogens from the blood that lets the immune system focus on covid-19. Alternatively, random cellular damage could clause a useful immune response. Etc etc.

Medicine has often found treatments that works without any real understanding of why.

Isn't this true of Pasteur and his initial application of vaccines?

While he identified the mechanism of inoculation, my understanding is he theorized that it was due to the attenuated pathogen outcompeting the virulent one for nutrients rather than due to stimulation of the immune system.

I think I got that from a lecture by a science historian once. This idea seems to be glossed in the Wikipedia article on Pasteur here:

https://en.wikipedia.org/wiki/Louis_Pasteur#Anthrax

Do I have that right?

>While he identified the mechanism of inoculation, my understanding is he theorized that it was due to the attenuated pathogen outcompeting the virulent one for nutrients rather than due to stimulation of the immune system.

How could it outcompete the actual virus if the actual virus isn't there yet at the time of vaccination?

Good point. Maybe the theory was the attenuated pathogen would consume available nutrients thereby depriving the real pathogen when it arrived?

Interesting, but if it boosts the immune system in the wrong way a side effect could possibly be a cytokine storm.

There are some indications that COVID-19 can already triggers cytokine storms by itself and that's what's killing some patients that seem to get better then crash.

Vitamin D?

Created in the skin, not blood.

Interesting, the vitamin letters were arbitrarily assigned but I wonder if we could back-cronym D to dermis

This virus has many skills.

It does directly infects kidney cells, and kidney failure is one common cause of death.

I think the current understanding is that the primary way that it kills is through circulatory system effects, blood clots that cause difficulty getting oxygen from the lungs, as well as strokes and heart attacks and other organ failures.

That's not an understanding, it's an observation and a very preliminary hypothesis for one of the major immediate causes of death. Huge difference.

Because of all the additional attention, it would be unsurprising for doctors to seemingly discover all kinds of previously unexamined phenomenon which have always been present, or to confuse increases in certain phenomenon as peculiar rather than simply reflecting the fact that you have a ton of patients with the same type of illness. For example, in one of the articles about blood clots a doctor is quoted as saying something to the effect of, "we're used to seeing these types of blood clots in the ICU, but only in 1 or 2 patients at a time, never in this number". For the sake of argument, maybe that's just because they've never had an entire ICU full of patients in viral-induced acute respiratory distress, that such blood clots happen to be more prevalent in such cases, and if you examined all such ICU patients over time (COVID, flu, w'ever), you'd see a similar pattern. (Because it's usually the elderly who die from respiratory infections, not alot of attention is paid to mechanisms of death. "Pneumonia" is something of a catch-all term, especially with an older cohort.) Maybe it's typical of anything that can incite such immune reactions--the article hinted that the mechanism may be related to how Ebola works, except with opposite outcomes (clots instead of bleeding out), which suggests the mechanism might be more a reflection of the severity of the distress than anything peculiar to the infectious agent, per se. Maybe younger cohorts are more likely to clot, but before COVID-19 they rarely died or had such severe symptoms, so nobody quantified prevalence. And if so, treating the clots might not significantly reduce fatality rates; or maybe it would, not just for COVID-19 but any similar viral ailment.

It could be part of the intubation process, if the patient is already that bad. Just theorizing.

The problem is the lungs are an incredible network of tunnels. If you spread out the surface area of your lungs, they would cover a tennis court (something I heard a long time ago, likely not exactly correct but generally right).

You could get UV light to the large bronchi but you couldn't get UV light into all the million little aveoli.

According to https://en.wikipedia.org/wiki/Lung, Estimates of the total surface area of lungs vary from 50 to 75 square metres (540 to 810 sq ft);[28][29] roughly the same area as one side of a tennis court. They then offer two references for this.

So you're off by a factor of 2 but are basically correct.

In the documentary movie Blade II, they show how UV light can go around corners if you make your light grenade strong enough.

UV light can go through the corners, and walls, if you make it strong enough. It could easily get into the smallest of aveoli. You may not have much of a lung left after that, though.

How about the patient breaths dilute Argon, and then excite it with a magnetic field so it lights up and create UV from inside the lungs? I think Argon is non toxic, and I think we’re only aiming for weak UV exposure.

And also, if you are intubating the person, they are probably pretty close to death. And then on top of that you paralyze them (with a medication, temporarily). So you are stopping their breathing. You have a few seconds in these people to get their lungs connected to mechanical ventilation. From what I've seen, if you don't, the outcomes are very bad.

This may be somewhat different from the typical intubation case, for example prior to surgery. Where its a generally more healthy person who has not been hypoxic for hours or days and is not at the last of their reserves...

Claims about the surface area of fractals are almost always true if generally interpreted. If you went down to the atomic scale you could probably calculate that the surface area of your lungs would cover the Earth. :)

The fractal structure of the lung ends with relatively smooth tissue after a finite amount of branching. So the usual arguments about fractals notwithstanding, there actually is a finite area to discuss that makes sense.

Sure, but if you look closer you will see that all of the cells have holes for stuff to go in and out, and the proteins sticking up from the surface have shapes, and so on. That's why I said "the atomic scale" not "the microscopic scale."

Any claim about surface area that relies on the examination at the atomic scale is no longer due to the fractal nature of the lung's branches. Such claims would be equality true (or false) of non-fractal organs.

On the atomic scale surfaces are not continuous so they don’t really have a surface area. You can’t infinitely zoom in like you can in a real fractal.

That assumes the fractal nature continues at all scales, which won't hold here I suspect (i.e. it's not enough for the structure to exist on those scales, the scaling properties have to continue for the geometry to be "fractal")

You wouldn't have lung tissue at that point. You'd have atoms that came from lung tissue.

If you blast a bright enough light it has the potential to penetrate extremely deeply. It would be a balancing act of maximizing luminosity while minimizing human tissue damage.

Are the internal structures of the lung all opaque to UVA light?

> Sars-Cov2 is a respiratory disease. I guess it maybe present in blood, but it doesn’t seem like removing it from blood would help with the respiratory issues it causes.

Biological systems are almost unimaginably complex. Unintuitive effects are not uncommon.

Isn't the respiratory issue caused by issues in the blood?

Totally agree, which is why I led with "which I will do for the point of this conversation, not that I believe it".

How does the virus get to the lungs? Directly via inhalation or via the blood stream?

Directly via inhalation, or by physical introduction of the virus from the hands onto a mucosal membrane (eyes, nose, mouth)

Presumably it depends on the virus, but tissues of the respiratory tract, from the nose/mouth all the way down to the lungs, have many of the same receptors. Typically a cold or flu virus infects the surface tissues in your nasal passages and then replicates its way down into your lungs, assuming it cares to reach that far.

At least, that's how someone who researched rhinoviruses once explained it to me many years ago, but probably using more accurate terminology.

Also, AFAIU, these viruses have also evolved other exploits. It's no coincidence that cold viruses induce sneezing and other sinus irritations; the viral fragments themselves have evolved to trigger this behavior, which is why it can happen after a live infection is gone--your tissues are still shedding viral fragments.

That appears to be the case. That's why you ought not touch your face or your nose, and why wearing a mask is recommended.