Moderators: richierich, ua900, PanAm_DC10, hOMSaR

 
User avatar
DocLightning
Posts: 21816
Joined: Wed Nov 16, 2005 8:51 am

Re: COVID-19 Vaccine News and Discussion Thread

Thu Apr 30, 2020 4:58 am

flyguy89 wrote:
Looks like the anti-viral Remdesivir is showing some positive results:


I've been bullish about it, but it does have some limitations.

1) I think it's important to understand that COVID-19 is a disease that comes in at least two parts. The first part is the initial immune response to the initial viral infection. For >80% of patients, it stops there. But for <20% of patients, even as they clear the virus, the immune system then runs off on a tangent and starts to activate a bunch of extraneous inflammatory responses that do nothing to help clear the infection but cause a lot of damage. Even for those who get really sick, their viral loads have usually dropped by a lot by day 14 or so. At this point, the disease switches from a viral disease per se to an inflammatory disease and at that point, the world's best antiviral isn't going to do much. So when I see trials enrolling patients out to 14 days after admission showing not much improvement, I'm not surprised. It's like saying that Usain Bolt isn't a fast runner because he can't outrun a Formula-1 racecar.

For influenza, all the antivirals must be given with 48h of the onset of symptoms or they offer no benefit. I suspect that remdesivir will help if given early in the course and post-marketing studies will need to be done to focus on the timecourse over which the drug ceases to offer much benefit.

2) Remdesivir is frightfully complex to synthesize, requiring eight steps, each of which reduces the total yield. Several of these steps take a few days, meaning that each batch takes a week. That is going to make it difficult to scale up production.

3) Remdesivir must be injected. It is typically given IV, although I would bet it would work intramuscularly (injected into a muscle). But that means that you can't just be sent home with a pack of pills. So that means that it can't be used for outpatient management to keep people who aren't yet sick from getting sick. Perhaps it could eventually be formulated into syringes or auto-pens for home injection, but that's a long way off.

4) Gilead, being Gilead, is going to charge an absurd sum for it.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
flyguy89
Posts: 2893
Joined: Tue Feb 24, 2009 6:43 pm

Re: COVID-19 Vaccine News and Discussion Thread

Thu Apr 30, 2020 5:17 am

DocLightning wrote:
flyguy89 wrote:
Looks like the anti-viral Remdesivir is showing some positive results:


I've been bullish about it, but it does have some limitations.

1) I think it's important to understand that COVID-19 is a disease that comes in at least two parts. The first part is the initial immune response to the initial viral infection. For >80% of patients, it stops there. But for <20% of patients, even as they clear the virus, the immune system then runs off on a tangent and starts to activate a bunch of extraneous inflammatory responses that do nothing to help clear the infection but cause a lot of damage. Even for those who get really sick, their viral loads have usually dropped by a lot by day 14 or so. At this point, the disease switches from a viral disease per se to an inflammatory disease and at that point, the world's best antiviral isn't going to do much. So when I see trials enrolling patients out to 14 days after admission showing not much improvement, I'm not surprised. It's like saying that Usain Bolt isn't a fast runner because he can't outrun a Formula-1 racecar.

For influenza, all the antivirals must be given with 48h of the onset of symptoms or they offer no benefit. I suspect that remdesivir will help if given early in the course and post-marketing studies will need to be done to focus on the timecourse over which the drug ceases to offer much benefit.

2) Remdesivir is frightfully complex to synthesize, requiring eight steps, each of which reduces the total yield. Several of these steps take a few days, meaning that each batch takes a week. That is going to make it difficult to scale up production.

3) Remdesivir must be injected. It is typically given IV, although I would bet it would work intramuscularly (injected into a muscle). But that means that you can't just be sent home with a pack of pills. So that means that it can't be used for outpatient management to keep people who aren't yet sick from getting sick. Perhaps it could eventually be formulated into syringes or auto-pens for home injection, but that's a long way off.

4) Gilead, being Gilead, is going to charge an absurd sum for it.

Interesting, thank you. Yes I had read that its effectiveness was tied to it being administered early on when symptoms first start appearing. I'll be interested to read more as the trial results are synthesized, but I suppose at this point, the more tools medical professionals can have in their arsenal to combat this the better. It certainly doesn't seem to be the silver bullet, but hopefully, even with its limitations, it'll be helpful, especially with everyone eyeing a second wave later in the year. And hopefully the sensitive public nature of the pandemic will pressure Gilead to not go overboard on price.

One thing I'm curious about however is, since much has been made of the fact that so many of the infections are asymptomatic, the transmission rate for those who show no symptoms. In other words, how much do we have to worry about asymptomatic cases? In my mind, since they're not coughing or sneezing like a symptomatic individual, the rate of virus transmission would be much lower in theory, no?
 
frmrCapCadet
Posts: 4105
Joined: Thu May 29, 2008 8:24 pm

Re: COVID-19 Vaccine News and Discussion Thread

Thu Apr 30, 2020 2:18 pm

Res anti-virals: for most of us how would we know we were in the first 48 hours of COVID-29 instead of flu, a cold, or just an off day? And early instructions were to call your doctor and wait and see if you really got sick. Even so the testing likely will take more, maybe far more, time than 48 hours. At this time I see no way to coordinate knowing you are ill, taking the test, and being treated with an anti-viral. Maybe I am missing something. The medicine we need is a more effected way of stopping "a bunch of extraneous inflammatory responses that do nothing to help clear the infection but cause a lot of damage"
Buffet: the airline business...has eaten up capital...like..no other (business)
 
User avatar
Francoflier
Posts: 5267
Joined: Wed Oct 31, 2001 12:27 pm

Re: COVID-19 Vaccine News and Discussion Thread

Thu Apr 30, 2020 3:59 pm

frmrCapCadet wrote:
how would we know we were in the first 48 hours of COVID-29


:scared: Please. One of these things per decade is largely enough, thank you....
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
User avatar
DocLightning
Posts: 21816
Joined: Wed Nov 16, 2005 8:51 am

Re: COVID-19 Vaccine News and Discussion Thread

Thu Apr 30, 2020 7:41 pm

flyguy89 wrote:
One thing I'm curious about however is, since much has been made of the fact that so many of the infections are asymptomatic, the transmission rate for those who show no symptoms. In other words, how much do we have to worry about asymptomatic cases? In my mind, since they're not coughing or sneezing like a symptomatic individual, the rate of virus transmission would be much lower in theory, no?


That, my friend, is a multimillion dollar question (literally). I think that the media and even experts speaking to the public have been framing this in a way that misdirects the discussion.

It isn't so much a question of whether asymptomatic carriers can spread the virus. The answer is simple: "yes!"

The multimillion dollar question is: "How good are asymptomatic carriers at spreading the virus as symptomatic people?" Better than the symptomatic? Worse? How much better or worse? How much variability is there in this from person to person? And a follow-up: "Exactly when and how?"

For example, very sick people tend to take to their beds (or hospitals) and thus are unlikely to come in contact with a lot of others, but they may be spreading more virus around their immediate environs, while asymptomatic people may be shedding relatively little virus, but they're doing it at home, at the gym, on the train to work, at the office, at the supermarket, at the PTA meeting, etc. So this becomes a matter of careful epidemiological study with mathematics that carries off into the almost metaphysical. It isn't an easy question to answer and by "not easy," I mean "expensive," among other things. Moreover, there is individual variation. Certainly, there are "Typhoid Maries" out there. There was one case in S. Korea (IIRC) where I guess they determined that an asymptomatic person walked through the Emergency Department, was in there for less than 20 seconds, and infected something like 15 people. But that doesn't mean that every asymptomatic carrier behaves in such a manner.

That said, there does seem to be an accumulating body of evidence that young kids are probably not a major vector for spread. Again, they probably can, but they seem to be very bad at it.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
DLFREEBIRD
Posts: 1455
Joined: Thu Mar 05, 2015 6:07 pm

Re: COVID-19 Vaccine News and Discussion Thread

Thu Apr 30, 2020 9:03 pm

sounds like "Typhoid Maries" are now "Asymptomatic Maries "
 
DLFREEBIRD
Posts: 1455
Joined: Thu Mar 05, 2015 6:07 pm

Re: COVID-19 Vaccine News and Discussion Thread

Fri May 01, 2020 7:59 pm

Ultraviolet blood irradiation (UBI) was extensively used in the 1940s and 1950s to treat many diseases including septicemia, pneumonia, tuberculosis, arthritis, asthma and even poliomyelitis.



The early studies were carried out by several physicians in USA and published in the American Journal of Surgery. However with the development of antibiotics, the use of UBI declined and it has now been called “the cure that time forgot”. Later studies were mostly performed by Russian workers and in other Eastern countries, and the modern view in Western countries is that UBI remains highly controversial. This review discusses the potential of UBI as an alternative approach to current methods used to treat infections, as an immune-modulating therapy and as a method for normalizing blood parameters.



Low and mild doses of UV kill microorganisms by damaging the DNA, while any DNA damage in host cells can be rapidly repaired by DNA repair enzymes. However the use of UBI to treat septicemia cannot be solely due to UV-mediated killing of bacteria in the bloodstream, as only 5–7% of blood volume needs to be treated with UV to produce the optimum benefit, and higher doses can be damaging. There may be some similarities to extracorporeal photopheresis (ECP) using psoralens and UVA irradiation. However there are differences between UBI and ECP in that UBI tends to stimulate the immune system, while ECP tends to be immunosuppressive. With the recent emergence of bacteria that are resistant to all known antibiotics, UBI should be more investigated as an alternative approach to infections, and as an immune-modulating therapy....



https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4783265/

thoughts?
 
User avatar
DocLightning
Posts: 21816
Joined: Wed Nov 16, 2005 8:51 am

Re: COVID-19 Vaccine News and Discussion Thread

Tue May 05, 2020 4:12 am

DLFREEBIRD wrote:
Ultraviolet blood irradiation (UBI) was extensively used in the 1940s and 1950s to treat many diseases including septicemia, pneumonia, tuberculosis, arthritis, asthma and even poliomyelitis.


So I've heard this brought up before. Generally speaking, as physicians, we like to have some biologically plausible idea of how a treatment works before we start using it. UBI was used decades ago without a good theory behind its mechanism because back then there weren't good tools to probe the general mechanism of treatments like these worked. After all, the structure of DNA was only elucidated in 1953.

I think it's worth looking into the older literature to determine 1) Was it even effective? I will point out that if it were very effective, we'd probably still be using it. The fact that it was supplanted by other techniques suggests that the use of antibiotics, pressors, anti-inflammatories and the like worked better with fewer effects. 2) How should this be done? 3) What are the risks? We certainly don't want to be setting off cancer or autoimmune disease or other immune dysfunction. And then 4) What is the mechanism of action?

There are a lot of older medical techniques that went by the wayside when more modern techniques came about. We no longer use gold preparations for rheumatologic disease because we have more effective and less toxic options. The same is true for arsenicals (arsenic preparations) or mercurials (mercury preparations) once used to treat things like syphilis. That said, there is some modern interest in re-examining arsenicals for use in cancer chemotherapy, but the new approach would be very different and utilize modern techniques (antibody-directed liposomal therapy) that would preferentially target these very toxic compounds at the tumor while avoiding healthy tissue.

So while I think that UBI merits some investigation, it's likely that we'll come up with something more understandable and with better-defined risks and benefits.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
flyguy89
Posts: 2893
Joined: Tue Feb 24, 2009 6:43 pm

Re: COVID-19 Vaccine News and Discussion Thread

Tue May 19, 2020 9:11 pm

So it looks like an mRNA vaccine under development by Moderna has shown some promise. Still very early on and not much on the way of hard data was released apparently, but certainly worth noting:

https://www.cnn.com/2020/05/18/health/c ... index.html

Researchers in China are also seeing some positive developments in creating neutralizing antibodies for use as a therapeutic:
https://www.yahoo.com/news/scientists-c ... 22069.html

I'm keeping my expectations on vaccine development very low at this point, but I'm certainly hopeful that at least one of the top candidates in testing now will prove effective enough.
 
LibertarianBorg
Posts: 1
Joined: Sat May 23, 2020 4:35 pm

Re: COVID-19 Vaccine News and Discussion Thread

Sat May 23, 2020 5:45 pm

DocLightning wrote:
flyguy89 wrote:
Looks like the anti-viral Remdesivir is showing some positive results:


2) Remdesivir is frightfully complex to synthesize, requiring eight steps, each of which reduces the total yield. Several of these steps take a few days, meaning that each batch takes a week. That is going to make it difficult to scale up production.



Having browsed and enjoyed this forum in the shadows for over 12 years now, I'll chime in on this one to elaborate for interested readers:

Yes, Remdesivir is a fairly sophisticated molecule, but I would not go as far as calling it "frightfully complex". A synthesis spanning eight steps is quite common. Furthermore, these eight steps are only the ones that are scrutinized by the authorities and/or patented. The molecules fed into the synthesis need to be manufactured as well, of course. This fact is most often overlooked in chemical literature - an "efficient n-step procedure" often means authors performed n steps based on commercially available molecules without considering the path of synthesis that had to be performed at the vendor of these compounds. Therefore, the number of steps for a drug starting from really simple molecules available in in multi-ton quantities will in fact be even higher. Eventually you will end up with crude oil, coal or plant/animal extracts at the beginning.

Chemical synthesis usually is not very efficient and say 70% is already satisfactory for most applications (it may be 99+% sometimes, 30% at other times). Eight steps @ 70% will give you a total yield of 0.7^8 * 100% = 5.8%. The rest will end up as waste together with solvents, auxiliaries and catalysts. So all other things assumed to be equal (e.g., molecular weight), for one batch of final product you will need 17-18 batches in the beginning of the sequence.

Reaction times will of course influence the time it takes to manufacture a drug, but are not the only contributing factor. If the whole world suddenly needs a supply of this drug, it will have to be manufactured at several places and the time it takes to ramp up production will be several months. I wonder how the industry will respond should this molecule indeed be found to offer therapeutic efficacy against COVID-19 (I do hope so, but this is not my field of study - back to you, Doc).
We are Borg. Assimilation will be based on informed consent, resistance is unnecessary.
 
PPVRA
Posts: 8483
Joined: Fri Nov 12, 2004 7:48 am

Re: COVID-19 Vaccine News and Discussion Thread

Sun May 24, 2020 3:59 am

Apparently melatonin may be able to help fight off the inflammation attack:

https://www.psychologytoday.com/us/blog ... t-covid-19
"If goods do not cross borders, soldiers will" - Frederic Bastiat
 
ltbewr
Posts: 15114
Joined: Thu Jan 29, 2004 1:24 pm

Re: COVID-19 Vaccine News and Discussion Thread

Sun May 24, 2020 1:22 pm

All of us have hope that somehow a viable vaccine will be available quickly but have many concerns about them.

Will it work. Will it give lasting immunity. Could it have have deadly or crippling side affects. Can it made quickly, on a large scale and safely. How do you create enough fast enough to give to 7 Billion people. Will you have enough PPE, trained persons, equipment to do distribution and inoculation. Many cannot take a 'live' virus as have autoimmune diseases. What will be the proper dose. Will many already distrustful of science and government reject getting it or only after months pass to assure its safe. Will getting the vaccine and proof of it be mandated to get or keep a job. If such proof is required, you know there will be many seeking fake papers so can get back to work. How much will it cost and who will pay for it. There is of course many who will say the richest will get the vaccine first, not first responders, EMT's, cops, food service and 'essential' workers or the oldest and sickest and from there how do you sort who is in priority order. Already we have see drug companies working on vaccines who are overplaying the results of the earliest of testing, maybe even lying, for financial advantage, company insiders who sell their stock on the uptick of its value from that news.

We are facing ethical, moral and financial horrors from the Covid-19 pandemic and even more in how to control, tread and vaccines to help us return to 'normal'..
 
User avatar
DocLightning
Posts: 21816
Joined: Wed Nov 16, 2005 8:51 am

Re: COVID-19 Vaccine News and Discussion Thread

Sun May 24, 2020 3:34 pm

PPVRA wrote:
Apparently melatonin may be able to help fight off the inflammation attack:

https://www.psychologytoday.com/us/blog ... t-covid-19


Yes, but the recommendation that healthcare workers take 40mg/day? Do you *really* want me making life-and-death decisions about your kid when I've taken that much melatonin?

There is also evidence that regular antihistamines (2nd generation, loratadine, fexofenadine, and especially cetirizine) may be helpful in averting the cytokine storm, and in more believable doses.

Then, someone is looking into the histamine H2-blocker famotidine, but don't go out and buy a bunch. This is given IV and in doses about 10x the usual.

It appears like the journey into a cytokine storm is a mathematically chaotic process in which there are at least three attractors. One of these is for critical severity with ventilator dependence, one of these is for moderate-to-severe severity without need for ventilator support, and one is for mild/asymptomatic cases. If my little model is true, then some small initial changes in the starting point (optimizing vitamin D levels, some cetirizine, maybe some melatonin) might be enough to tip the trajectory to one of the latter two attractors.

ltbewr wrote:
All of us have hope that somehow a viable vaccine will be available quickly but have many concerns about them.

Will it work. Will it give lasting immunity. Could it have have deadly or crippling side affects. Can it made quickly, on a large scale and safely.


All very valid questions. The leading candidates take an approach that is somewhat different from most existing vaccines. They use viral genetic sequences to force the patient's cells to start expressing SARS-CoV-2 S protein. This has some significant advantages over just injecting S protein. In other posts, I have spoken about the "two arms" of adaptive immunity, the cell-mediated arm (T cells) and the humoral arm (antibodies). When you just inject a protein, you get humoral immunity, but not fantastic cell-mediated immunity. But when you force cells in the patient to express viral proteins, you get both cell-mediated and humoral immunity.

In the past, live-attenuated vaccines have been used to this end, but those vaccines do contain the actual proteins against which these immune responses will be directed. These newer approaches only contain the genetic code, which is interesting, and at least in the Moderna version, might lead to better effect from a booster dose because existing antibodies will not inactivate the second dose of the vaccine before it can reach its target. The Oxford vaccine uses an adenovirus, and it's likely that the patient will develop anti-adenovirus antibodies that make boosting more challenging.

It's not likely to have worse side-effects than getting the actual illness. I'd say that my big worry is setting off this inflammatory cascade with the vaccine, but I'm going to guess that the risk will be much lower with the vaccines because the vaccines cannot replicate, so the inflammatory response that they trigger will be brief and mild. However, some people may react badly to it, but those people would also probably react badly to getting COVID-19.

Certainly, the scaling is also a valid concern, and I sincerely hope that manufacturers who produce syringes and needles are ramping up production. Consider this: if you can make one million doses a day, you will need about three years to make one billion doses.

But here is my take on the vaccine and what it will and will not do: from the Oxford data, it appears that the vaccine does not provide complete sterilizing immunity against infection with the virus. Sterilizing immunity is akin to what you get from a measles vaccine. If you get two doses of measles vaccine and then I have someone with measles cough in your face, the virus might get as far as infecting a couple of cells in your nose and then be completely wiped out before it can complete even one round of replication.

But with these vaccines, they found that the monkeys that they challenged with the virus did get infected with it. However, those animals did not get pneumonia. They had viral replication in their noses and that's all. That's consistent with prior studies of endemic human coronaviruses, where antibody titers fall after some time, but repeat infection results in mild or subclinical (asymptomatic, or inapparent) infection. And this is not completely unprecedented. Flu shots are not very good at preventing infection with influenza, but they are very effective at preventing severe influenza pneumonia.

So that means that this vaccine will probably stop you from getting severe COVID-19. It may reduce the amount of viral replication in the nose and by that route reduce shedding, but I don't think that it will completely stop infection and shedding.

That means that the vaccine will likely protect those who get it, but it won't protect those who don't get it, like the measles vaccine does. The entire concept of "herd immunity" might not work with this vaccine very well.

The other thing is that we aren't going to have a good idea of how long this protection lasts when the first doses of vaccine are given to the general public (which I predict will be sometime between Christmas and Valentine's Day).

So all of this raises some public policy issues. Do we require people to get the vaccine before they can get on an airplane? Before they can go to the barber? Before they can go to the gym? How do we enforce that? Or do we just say: "Don't get the vaccine at your own risk"? As pro-vaccine as I am, I'm not comfortable with using heavy-handed tactics to require people to take such a new vaccine with so little clinical data behind it. I probably will take either the Oxford or Moderna (I'd prefer the Moderna) but I'm a physician and a former molecular virologist and I have a very sophisticated understanding of these matters.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
StarAC17
Posts: 3810
Joined: Thu Aug 07, 2003 11:54 am

Re: COVID-19 Vaccine News and Discussion Thread

Sun May 24, 2020 8:40 pm

DocLightning wrote:


Certainly, the scaling is also a valid concern, and I sincerely hope that manufacturers who produce syringes and needles are ramping up production. Consider this: if you can make one million doses a day, you will need about three years to make one billion doses.

But here is my take on the vaccine and what it will and will not do: from the Oxford data, it appears that the vaccine does not provide complete sterilizing immunity against infection with the virus. Sterilizing immunity is akin to what you get from a measles vaccine. If you get two doses of measles vaccine and then I have someone with measles cough in your face, the virus might get as far as infecting a couple of cells in your nose and then be completely wiped out before it can complete even one round of replication.

But with these vaccines, they found that the monkeys that they challenged with the virus did get infected with it. However, those animals did not get pneumonia. They had viral replication in their noses and that's all. That's consistent with prior studies of endemic human coronaviruses, where antibody titers fall after some time, but repeat infection results in mild or subclinical (asymptomatic, or inapparent) infection. And this is not completely unprecedented. Flu shots are not very good at preventing infection with influenza, but they are very effective at preventing severe influenza pneumonia.

So that means that this vaccine will probably stop you from getting severe COVID-19. It may reduce the amount of viral replication in the nose and by that route reduce shedding, but I don't think that it will completely stop infection and shedding.

That means that the vaccine will likely protect those who get it, but it won't protect those who don't get it, like the measles vaccine does. The entire concept of "herd immunity" might not work with this vaccine very well.



Could a covid19 vaccine by given in a different manner such as a nasal spray?

Why is the measles vaccine so effective and the immune response so swift that there would not even be any viral replication? Is it because that virus is much more stable and less prone to mutation?

I would assume the latter where you would still get infected but have a strong enough immune response to contain the virus that you might not even notice. The thing with covid19 is how contagious if you are asymptomatic or pre-symptomatic, I heard about up to 40% of spread is comes from those with no symptoms. Also the long incubation time does us no favours.
Engineers Rule The World!!!!!
 
User avatar
DocLightning
Posts: 21816
Joined: Wed Nov 16, 2005 8:51 am

Re: COVID-19 Vaccine News and Discussion Thread

Mon May 25, 2020 12:57 am

StarAC17 wrote:
Could a covid19 vaccine by given in a different manner such as a nasal spray?


That is a very good question and I have been wondering why it isn't. Needles seem to be the standard, but I feel like not enough researchers ask why. It's not just that needles hurt and scare people, but is injecting an antigen (or a vector) into skeletal muscle really the best way to get wide immunity?

StarAC17 wrote:
Why is the measles vaccine so effective and the immune response so swift that there would not even be any viral replication? Is it because that virus is much more stable and less prone to mutation?


Nothing like that. If anything, coronaviruses are more stable than the paramyxoviruses that make up measles and mumps. But measles isn't just a respiratory illness. It's a systemic illness. The wild-type illness involves invasion of the blood. As soon as it tries to do that, it finds circulating antibodies and gets bound up. Also the measles vaccine uses a live, attenuated strain. The issue with using live, attenuated strains is that the strains have to be bred and selected very carefully. That said, if I spray wild measles into the face of someone who is vaccinated, they will probably have a small amount of viral replication in the nose before the immune system quickly stops it. But if I try that same trick a month later, they will now have mucosal antibodies that prevent even that. A different paramyxovirus, respiratory syncytial virus (RSV), has undergone multiple rounds of attenuation and it always comes out either over attenuated or under attenuated. It's a tough balance. However, when we do get a vaccine for it, my guess is that it will be given as a nasal spray of some sort. But RSV is a primarily respiratory virus that doesn't normally enter the blood and the same is true for the coronavirus in question (when it does, it wreaks all kinds of havoc).

I would assume the latter where you would still get infected but have a strong enough immune response to contain the virus that you might not even notice. The thing with covid19 is how contagious if you are asymptomatic or pre-symptomatic, I heard about up to 40% of spread is comes from those with no symptoms. Also the long incubation time does us no favours.


Right, and so I am hoping that through mechanisms similar to measles vaccination, we will get minimal and brief replication of SARS-CoV-2 in the nasal mucosa and rapid clearance. But we just don't know that yet. I will point out that in the macaque studies, they used huge doses of SARS-CoV-2 in their challenges. In reality, you're likely to be infected by a droplet with no more than a few thousand virus particles, so we may see that at least having been primed by the vaccine enables a rapid cell-mediated response that stamps down on viral replication before it can get big enough to be contagious. Time will tell.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
StarAC17
Posts: 3810
Joined: Thu Aug 07, 2003 11:54 am

Re: COVID-19 Vaccine News and Discussion Thread

Mon May 25, 2020 2:07 am

StarAC17 wrote:
Could a covid19 vaccine by given in a different manner such as a nasal spray?


That is a very good question and I have been wondering why it isn't. Needles seem to be the standard, but I feel like not enough researchers ask why. It's not just that needles hurt and scare people, but is injecting an antigen (or a vector) into skeletal muscle really the best way to get wide immunity?


It's not a viral disease but when I got the Typhoid vaccine to travel to Kenya in 2018 it was 4 pills that I had to take every other day over the course of a week.

However, when we do get a vaccine for it, my guess is that it will be given as a nasal spray of some sort. But RSV is a primarily respiratory virus that doesn't normally enter the blood and the same is true for the coronavirus in question (when it does, it wreaks all kinds of havoc).


That makes sense, we know while primary a respiratory virus the flu does cause aches and pains that means its attacking muscles and joints so that is why the needle works.
As you say Covid19 wreaks havoc in the blood causing clotting potentially causing adrenal failure, strokes, the inflammation we are seeing in kids etc. You put an attenuated vaccine in the bloodstream then it might cause lots of problems.

. In reality, you're likely to be infected by a droplet with no more than a few thousand virus particles, so we may see that at least having been primed by the vaccine enables a rapid cell-mediated response that stamps down on viral replication before it can get big enough to be contagious. Time will tell.


It seems to me that those who have got this and recovered have both antibodies and T-cell immunity so the stories of immediate re-infection are pretty much shot down now.

I think that some of the trials have showed especially with the new RNA based vaccine (the Moderna) to show both a T-cell and antibody response to the vaccine. Whether or not those trials are effective in fighting Covid19 have yet to be determined.
Engineers Rule The World!!!!!
 
flyguy89
Posts: 2893
Joined: Tue Feb 24, 2009 6:43 pm

Re: COVID-19 Vaccine News and Discussion Thread

Mon Jun 01, 2020 5:55 am

This article was making the rounds today:

New coronavirus losing potency, top Italian doctor says
https://news.yahoo.com/coronavirus-losi ... 58113.html

I'm not exactly sure what they're trying to say however...that it's mutated to something less fatal?
 
DLFREEBIRD
Posts: 1455
Joined: Thu Mar 05, 2015 6:07 pm

Re: COVID-19 Vaccine News and Discussion Thread

Mon Jun 01, 2020 6:20 am

That's wonderful
 
User avatar
DocLightning
Posts: 21816
Joined: Wed Nov 16, 2005 8:51 am

Re: COVID-19 Vaccine News and Discussion Thread

Tue Jun 02, 2020 3:17 am

flyguy89 wrote:
This article was making the rounds today:

New coronavirus losing potency, top Italian doctor says
https://news.yahoo.com/coronavirus-losi ... 58113.html

I'm not exactly sure what they're trying to say however...that it's mutated to something less fatal?


I am skeptical.

Folks, there is one strain of SARS-CoV-2. There are many miniature variations, but none that have been conclusively shown to modify the disease severity or transmissibility.

Now, the natural history of most emergent viruses into a new species is that they will tend to self-attenuate. Viruses require living hosts and so it makes little sense to kill your host.

StarAC17 wrote:
It's not a viral disease but when I got the Typhoid vaccine to travel to Kenya in 2018 it was 4 pills that I had to take every other day over the course of a week.


It's bacterial and it's attenuated, but I think it illustrates my point: if we want mucosal immunity, why aren't we applying these viral vectors to the mucosa?

StarAC17 wrote:
That makes sense, we know while primary a respiratory virus the flu does cause aches and pains that means its attacking muscles and joints so that is why the needle works.


Not necessarily. The joint aches (arthralgia) and muscle pain (myalgia) is more a factor of various inflammatory signaling molecules called cytokines, especially interferon. We don't isolate influenza from joint spaces. Those aches and pains are nature's way of telling you to slow the hell down and conserve energy.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan

Who is online

Users browsing this forum: art, Dano1977, Dutchy, KFTG, scbriml and 57 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos