[MarkJerling]

Thank you, that makes sense. The calculated efficacy obviously depends on the the two vaccine shots being given at the recommended interval. In the UK they have decided not to bother too much about that and have extended the interval between shots to 12 weeks so nobody knows how much protection that gives.

I know they have also been doing test on whether the second dose works best as a full dose or a half dose. Some studies seem to suggest that a 1/2 dose as the second shot works even better than a full dose with one of the vaccines at least.

[slartibartfast01]

I know they have also been doing test on whether the second dose works best as a full dose or a half dose. Some studies seem to suggest that a 1/2 dose as the second shot works even better than a full dose with one of the vaccines at least.

There were reports that a half dose of the Astra Zeneca vaccine followed by a full dose was more effective but not much has been said about that recently. "Experts" have also said that increasing the interval between doses is more effective which is suspiciously fortunate considering the UK's strategy. The rest of the world can observe how well the strategy works.

[Rondec]

How do they test the efficacy of a vaccine? Do they deliberately try to infect volunteers in trials?

The articles on the two vaccines were published in the New England Journal of Medicine. This is the one on the Pfizer vaccine: https://www.nejm.org/doi/full/10.1056/NEJMoa2034577 This is on the Moderna: https://www.nejm.org/doi/full/10.1056/NEJMoa2035389

I think Mark did a good job of explaining it. They recruited volunteers in communities in high levels of COVID, gave have of them placebo shots and half vaccinations and then waited till a certain number of people in the study had developed COVID-19. At that point they broke down what percent were in the vaccinated group and what percent were in the placebo group. Because of the high levels of COVID in our communities, it didn't take to long to get to those points.

---------- Post added 01-18-21 at 05:38 AM ----------

There were reports that a half dose of the Astra Zeneca vaccine followed by a full dose was more effective but not much has been said about that recently. "Experts" have also said that increasing the interval between doses is more effective which is suspiciously fortunate considering the UK's strategy. The rest of the world can observe how well the strategy works.

I think that protocol is what they are using. I think there is some concern about the data on AZ's vaccine. So, they had a plan to give all of the volunteers two full doses. It turned out that if you got two full doses of the vaccine, it was 60-ish percent effective.

By accident, they gave 1300 people a half dose followed by a full dose and in that small segment, the vaccine seemed to be 90 percent effective. Now, those were all younger people (under 55) and a relatively small portion of the study and so I do think it is an open question as to how much more effective that protocol is than the other. How the Oxford/AstraZeneca vaccine went from pole position to troubled start

[Jonathan Mac]

The articles on the two vaccines were published in the New England Journal of Medicine. This is the one on the Pfizer vaccine: https://www.nejm.org/doi/full/10.1056/NEJMoa2034577 This is on the Moderna: https://www.nejm.org/doi/full/10.1056/NEJMoa2035389

I think Mark did a good job of explaining it. They recruited volunteers in communities in high levels of COVID, gave have of them placebo shots and half vaccinations and then waited till a certain number of people in the study had developed COVID-19. At that point they broke down what percent were in the vaccinated group and what percent were in the placebo group. Because of the high levels of COVID in our communities, it didn't take to long to get to those points.

---------- Post added 01-18-21 at 05:38 AM ----------



I think that protocol is what they are using. I think there is some concern about the data on AZ's vaccine. So, they had a plan to give all of the volunteers two full doses. It turned out that if you got two full doses of the vaccine, it was 60-ish percent effective.

By accident, they gave 1300 people a half dose followed by a full dose and in that small segment, the vaccine seemed to be 90 percent effective. Now, those were all younger people (under 55) and a relatively small portion of the study and so I do think it is an open question as to how much more effective that protocol is than the other. How the Oxford/AstraZeneca vaccine went from pole position to troubled start

Yes, a half dose followed by a full seems to be the best bet for the AZ vaccine but I don't think they know why yet, it will be interesting to see. Still, if there are no negative effects from doing that way then there's no reason not to proceed, even if the reason is not known. I would like to know how they establish what amount constitutes "one dose".

The AZ vaccine is unlike the Pfizer and Moderna ones as it inserts the genes coding for the spike protein in a harmless virus, so it includes all the other genes that said virus. I have read some reports that suggest the possibility of SARS-CoV-2 and other coronaviruses, such as those that cause the common cold, possess genes which weaken the immune response, so it is essentially defending itself against the host's immune response. It has been theorised that this is the reason why we can catch a cold repeatedly: the immune response is not lasting. Unlike the flu, which re-infects by continually mutating, coronaviruses do not do this, they have developed this alternative strategy. The impact this could have on vaccines, and time will tell if it's the case, is that protection provided by the AZ vaccine may be much more short-live than that from the mRNA vaccines, which contain only the genes coding for the spike protein and none of the others.

It will be very interesting to see.

For now, at least in Europe, it's not possible to choose which vaccine you are given, and that makes sense at this stage with the virus running rampant and vaccines in short suppy. However, if I were given a choice I would certainly pick one of the mRNA vaccines over the AZ one.

[Rondec]

Yes, a half dose followed by a full seems to be the best bet for the AZ vaccine but I don't think they know why yet, it will be interesting to see. Still, if there are no negative effects from doing that way then there's no reason not to proceed, even if the reason is not known. I would like to know how they establish what amount constitutes "one dose".

The AZ vaccine is unlike the Pfizer and Moderna ones as it inserts the genes coding for the spike protein in a harmless virus, so it includes all the other genes that said virus. I have read some reports that suggest the possibility of SARS-CoV-2 and other coronaviruses, such as those that cause the common cold, possess genes which weaken the immune response, so it is essentially defending itself against the host's immune response. It has been theorised that this is the reason why we can catch a cold repeatedly: the immune response is not lasting. Unlike the flu, which re-infects by continually mutating, coronaviruses do not do this, they have developed this alternative strategy. The impact this could have on vaccines, and time will tell if it's the case, is that protection provided by the AZ vaccine may be much more short-live than that from the mRNA vaccines, which contain only the genes coding for the spike protein and none of the others.

It will be very interesting to see.

For now, at least in Europe, it's not possible to choose which vaccine you are given, and that makes sense at this stage with the virus running rampant and vaccines in short suppy. However, if I were given a choice I would certainly pick one of the mRNA vaccines over the AZ one.

I guess the thing that I question is how much data we really have on the half dose version -- only 1300 people and all of them younger doesn't feel adequate. I suppose in these crazy times, we just need to get vaccines out there the best we can and continue to track them after release to be sure we are doing the best with them.

(I'm not saying there would be side effects with a lower dose, just that if you include older patients in the trial the effectiveness might drop considerably compared to what they saw with this very small sample of people).

[Serkevan]

Yes, a half dose followed by a full seems to be the best bet for the AZ vaccine but I don't think they know why yet, it will be interesting to see. Still, if there are no negative effects from doing that way then there's no reason not to proceed, even if the reason is not known. I would like to know how they establish what amount constitutes "one dose".

I was reading about the reason for the AZ dosing mistake.

They didn't make a proper calibration curve for the spectrometer they were using (in short and very loosely, the number of viral particles can be correlated to the blocking of light at certain wavelengths, but one of the other components was throwing off the measurement and they didn't check the effect of the other components separately to correct the results*). I'm not really knowledgeable about immunology, but I assume that phase 1 studies already look for which vaccine dosage is needed to generate an immune response - basically you need enough viral load to allow something to survive long enough to be presented to the relevant cells (and not get destroyed by the nonspecific response too quickly), but not so high that you risk a full reaction that gets everyone sick for some days.


*This is a very rookie mistake, which means it was probably a very-overworked-and-stressed-out mistake in this situation. Still, I'm sure someone has been wishing for the Earth to swallow them for a while...

[35mmfilmfan]

On last night's TV news, there was a report of a new 'Walk In' vaccination centre in Norwich, so I defied the current lockdown and went there.

Firstly, the Television News had given the wrong address - not helpful, and no-one there knew where it actually was. Eventually asked at local apothecary, who directed me to the correct site (in a shopping centre, no less - definitely a sterile area). This shopping centre used to have an NHS Walk-In treatment area for minor issues, so logic indicated the vaccination station would be there. Not at all.

It was actually being held in the Food Hall (with numerous fast food outlets and the adjacent seating areas). I approached the receptionist, and politely explained that I had come for my vaccination. She looked at me and demanded 'Letter'. I enquired 'What letter ?' and was told, as if this were current knowledge, that attendance and treatment were to follow a letter advising me I was due. I asked who the letter came from, but this she did not know.

So, to sum up - I am seventy years old, suffer from COPD and emotional issues, and also have mobility issues, so am in a high-risk group for this virus - and I cannot obtain the vaccination due to rampant mindless beaurocracy.

If I don't post again, you'll know why.

I am beginning to wonder if NHS stands for No Help Sucker ?

[slartibartfast01]

On last night's TV news, there was a report of a new 'Walk In' vaccination centre in Norwich, so I defied the current lockdown and went there.

Firstly, the Television News had given the wrong address - not helpful, and no-one there knew where it actually was. Eventually asked at local apothecary, who directed me to the correct site (in a shopping centre, no less - definitely a sterile area). This shopping centre used to have an NHS Walk-In treatment area for minor issues, so logic indicated the vaccination station would be there. Not at all.

It was actually being held in the Food Hall (with numerous fast food outlets and the adjacent seating areas). I approached the receptionist, and politely explained that I had come for my vaccination. She looked at me and demanded 'Letter'. I enquired 'What letter ?' and was told, as if this were current knowledge, that attendance and treatment were to follow a letter advising me I was due. I asked who the letter came from, but this she did not know.

So, to sum up - I am seventy years old, suffer from COPD and emotional issues, and also have mobility issues, so am in a high-risk group for this virus - and I cannot obtain the vaccination due to rampant mindless beaurocracy.

If I don't post again, you'll know why.

I am beginning to wonder if NHS stands for No Help Sucker ?

I am surprised it was described as "walk in". It is another vaccination hub like the seven announced last week.

[35mmfilmfan]

I am surprised it was described as "walk in". It is another vaccination hub like the seven announced last week.

I think this may have been to indicate that it was not a 'Drive Through' centre. The nearest Covid testing centre is at a sprawling Hospital complex well outside the city centre, and is set up purely for the convenience of motorists. When a friend and I visited a couple of weeks ago, since she had been instructed to have the test prior to an investigative procedure which she was due, we had to walk for over a mile from the main buildings, with no signposts directing us, asking various members of staff, few of whom knew anything about it. We eventually found it, and were told by the staff that we should not have left our car, but should have driven there.

We explained we are neither of us drivers, and they looked astounded, and had to find a chair for my friend to sit on. Again, as I had no appointment letter, they refused to test me.

is it any wonder that the infection rate is rising so rapidly in and around Norwich ?

Sorry if this rant has deviated somewhat from the OP's intention.

[ZombieArmy]

Yes, a half dose followed by a full seems to be the best bet for the AZ vaccine but I don't think they know why yet, it will be interesting to see. Still, if there are no negative effects from doing that way then there's no reason not to proceed, even if the reason is not known. I would like to know how they establish what amount constitutes "one dose".

The AZ vaccine is unlike the Pfizer and Moderna ones as it inserts the genes coding for the spike protein in a harmless virus, so it includes all the other genes that said virus. I have read some reports that suggest the possibility of SARS-CoV-2 and other coronaviruses, such as those that cause the common cold, possess genes which weaken the immune response, so it is essentially defending itself against the host's immune response. It has been theorised that this is the reason why we can catch a cold repeatedly: the immune response is not lasting. Unlike the flu, which re-infects by continually mutating, coronaviruses do not do this, they have developed this alternative strategy. The impact this could have on vaccines, and time will tell if it's the case, is that protection provided by the AZ vaccine may be much more short-live than that from the mRNA vaccines, which contain only the genes coding for the spike protein and none of the others.

It will be very interesting to see.

For now, at least in Europe, it's not possible to choose which vaccine you are given, and that makes sense at this stage with the virus running rampant and vaccines in short suppy. However, if I were given a choice I would certainly pick one of the mRNA vaccines over the AZ one.

Yeah but the AZ vaccine is far cheaper at about 2.38 per dose as opposed to over 20 for the mRNA ones. The AZ/J&J ones are also far easier to produce and will be produced in the billions by countries all over the world.

Plus, they're far easier to store since they can be stable at regular freezer temperatures rather than the deep freeze temps of the mRNA vaccines which makes deploying it much easier.

I think if it turns out we need to be revaccinated every 6 months it won't be the biggest deal.

[Cerebum]

Yeah but the AZ vaccine is far cheaper at about 2.38 per dose as opposed to over 20 for the mRNA ones. The AZ/J&J ones are also far easier to produce and will be produced in the billions by countries all over the world.

Plus, they're far easier to store since they can be stable at regular freezer temperatures rather than the deep freeze temps of the mRNA vaccines which makes deploying it much easier.

I think if it turns out we need to be revaccinated every 6 months it won't be the biggest deal.

Also, once the r number is way down, repeat vaccination will come down to choice, much like the flu jab.

[slartibartfast01]

Also, once the r number is way down, repeat vaccination will come down to choice, much like the flu jab.

I wonder if a yearly vaccination would only be a booster requiring one shot. That would make it a lot more practical.

[Serkevan]

Yeah but the AZ vaccine is far cheaper at about 2.38 per dose as opposed to over 20 for the mRNA ones. The AZ/J&J ones are also far easier to produce and will be produced in the billions by countries all over the world.

Plus, they're far easier to store since they can be stable at regular freezer temperatures rather than the deep freeze temps of the mRNA vaccines which makes deploying it much easier.

I think if it turns out we need to be revaccinated every 6 months it won't be the biggest deal.

AFAIK the only -80°C vaccine is the BioNTech one, no? The Moderna shot holds at -18°C and then can be kept at fridge temp for a month.

Coincidentally, my uncle works in industrial refrigeration and the -80 freezers aren't *that* complicated to make, they are making relatively small units (I think he mentioned 1 m³ containers?) these days, to make distribution easier for places where they don't have deep freezers yet. They were designed within weeks, it's well known tech by now.

[Rondec]

AFAIK the only -80°C vaccine is the BioNTech one, no? The Moderna shot holds at -18°C and then can be kept at fridge temp for a month.

Coincidentally, my uncle works in industrial refrigeration and the -80 freezers aren't *that* complicated to make, they are making relatively small units (I think he mentioned 1 m³ containers?) these days, to make distribution easier for places where they don't have deep freezers yet. They were designed within weeks, it's well known tech by now.

That's correct.

The Moderna vaccine is kept at the same temperature as other frozen vaccines, like Varicella and MMR. Any office that can handle those should be able to handle the Moderna vaccine.

I think the biggest thing that mRNA vaccines bring to the table is flexibility. That is to say, if a strain of COVID shifts the spike protein enough that the vaccines no longer cover it, it is a pretty simple thing to sequence the different spike protein and shift the mRNA to cover that. It could probably be done in a couple of months, whereas with standard vaccinations it would probably take quite a bit longer.

I hope that doesn't happen, but there was some concern that the South African strain had shifted enough that the vaccine might not cover it. I am sure bigger mutations will come in the future. It's just what happens with these things.

[MarkJerling]

AFAIK the only -80°C vaccine is the BioNTech one, no? The Moderna shot holds at -18°C and then can be kept at fridge temp for a month.

Coincidentally, my uncle works in industrial refrigeration and the -80 freezers aren't *that* complicated to make, they are making relatively small units (I think he mentioned 1 m³ containers?) these days, to make distribution easier for places where they don't have deep freezers yet. They were designed within weeks, it's well known tech by now.

I do wonder how they do it. Can you get him to explain how they manage to cool that low?