Vaccine trials volunteers

[Swinglowandslow]

I saw reports re Pfizer's progress re vaccine trials. Very good news.
Couple of questions re trials that maybe an expert could answer.
Some volunteers are given a placebo, most a vaccine. I take it that results are determined by looking for and detecting antibodies , T cells etc. ?And not by exposing to the virus!!?

And that the presence of antibodies etc is enough to determine immunity?

 

[sweaty sock]

Guessing... we know what the antibodies look like, can test and detect them from healthy volunteers who have already had covid.

People in the study are given the vaccine (or not if they are placebo group) and tested to see if the bodys response is to produce the correct antibody, thus protecting agains real virus. If it does and has no side effects then hey presto. The vaccine while not the corona virus is in effect a clue to the body what it needs to do.

Possibly the most simplified and generalised decription of virology ever. Apols to everyone involved.

 

[Swinglowandslow]

Guessing... we know what the antibodies look like, can test and detect them from healthy volunteers who have already had covid.

People in the study are given the vaccine (or not if they are placebo group) and tested to see if the bodys response is to produce the correct antibody, thus protecting agains real virus. If it does and has no side effects then hey presto. The vaccine while not the corona virus is in effect a clue to the body what it needs to do.

Possibly the most simplified and generalised decription of virology ever. Apols to everyone involved.

You and I must have graduated from the same Virology class?.
Hopefully, Ethan will tell us if we wasted our time or not!

 

[doublebogey7]

It's my understanding that half the volunteers (around 22,500) were given the vacine and half the placebo. In addition to testing for antibodies, they are able to say that it is effective as only a very small number of those who received the vaccine have subsequently caught the virus, where as a much larger number who received the placebo got it.

 

[Swinglowandslow]

It's my understanding that half the volunteers (around 22,500) were given the vacine and half the placebo. In addition to testing for antibodies, they are able to say that it is effective as only a very small number of those who received the vaccine have subsequently caught the virus, where as a much larger number who received the placebo got it.

What?
I think that can't be right. These vaccines are 90-95 per cent effective, apparently.
Which means if all those given the vaccine were exposed to the virus about 1125 would have caught it.
But that would not have happened. No way would all have been exposed to the virus. And I don't see how it was known how many had been exposed to it in everyday living.
Ethan, where are you ?.?

 

[Ethan]

What?
I think that can't be right. These vaccines are 90-95 per cent effective, apparently.
Which means if all those given the vaccine were exposed to the virus about 1125 would have caught it.
But that would not have happened. No way would all have been exposed to the virus. And I don't see how it was known how many had been exposed to it in everyday living.
Ethan, where are you ?.?

The 90 or 95% is the difference between the number on placebo/control who got Covid versus those on the vaccine. Doublebogey scored a birdie with his comment, he is quite right. The numbers for both the Moderna and BioNTech/Pfizer programmes were similar, about 5 or 6 Covid cases in the vaccine group and just under 100 in the control group. These are very impressive numbers.

The design of both studies was based on the difference in event rate, so each had an analysis set a certain number of cases. The Moderna study was designed based on an assumption that the vaccine would be about 60% effective (a standard decent vaccine assumption), so 160 or so cases of Covid were needed to be able to tell if there was a clear difference. But because it was more effective than 60%, they got the answer with fewer cases. Both studies will continue so they can see more cases, so the 90/95% number may change a bit, but probably not a lot. The other good news is that those who got the vaccine and still got Covid appear to have a less severe case. OK, not very many cases to be sure, but the possibility is that the vaccine was still mitigating the illness in them. That would be very promising news.

The results of the Oxford/AZ will come through soon. Hopefully it will be in the same ballpark. The media has got a bit excited with the 90 vs 95% race. In the real world, these numbers are the same. If Oxford comes in a good bit lower, say around that 60 or 70%, some decisions on prioritisation will be needed.

 

[ManinBlack]

If the vaccine is 90% to 95% effective you would expect that, in the placebo group, there would be between 10 & 20 times the number of people contracting the virus, assuming that the same number in each group were exposed to the virus. I assume that this is the sort of result the trial came up with since this is the only way the 90% to 95% figure could be arrived at.

 

[ManinBlack]

If the vaccine is 90% to 95% effective you would expect that, in the placebo group, there would be between 10 & 20 times the number of people contracting the virus, assuming that the same number in each group were exposed to the virus. I assume that this is the sort of result the trial came up with since this is the only way the 90% to 95% figure could be arrived at.

Ethan beat me to it!

 

[Swinglowandslow]

Double bogey, my apologies?.

 

[MC72]

Does anyone know what MRC-5 is, in relation to the vaccines that are being proposed?

 

[Ethan]

Does anyone know what MRC-5 is, in relation to the vaccines that are being proposed?

It is a cell culture used in the manufacture of various established vaccines and some Covid vaccines, usually to incubate a viral vector carrying some part of the target virus. It is not an ingredient of the vaccine as such, but is involved in the production line, as it were.

 

[MC72]

It is a cell culture used in the manufacture of various established vaccines and some Covid vaccines, usually to incubate a viral vector carrying some part of the target virus. It is not an ingredient of the vaccine as such, but is involved in the production line, as it were.

Could you explain what you mean by cell culture - is it grown or initiated in a lab?

 

[Ethan]

Could you explain what you mean by cell culture - is it grown or initiated in a lab?

Biological, which means protein or cell based, medicines, stuff like the meds Phil Mick took for his psoriatic arthropathy, interferon for MS and vaccines which contain virus, amongst others, need to be grown, fermented or allowed to propagate in a controlled environment. Pills, on the other hand, are just a bunch of chemicals made on a factory production line and can be reliably made all day long.

There are a range of different cell lines which are well understood and reliable with different properties which suit different products. The cell lines come from different sources, some animal, some human, some a mix of both (i.e. modified to give specific functions). They are usually cells which were identified during investigation of a patient to have special properties. One of the famous ones is the HeLa cell, which is a so-called immortal cell line (really means very durable) that came from a cancer patient in the 1950s and has been used in research ever since. These cell lines have the advantage of producing identical cells, so can be compared against one another in different experiments. Some other cell lines come from fetal samples and MRC-5 is one of those. I don't know the details of exactly which Covid vaccines use MRC-5 in their manufacture, but I would guess that some that use virus, for example the Oxford/AZ one, might use MRC-5 as a vehicle for that virus to replicate in.

 

[ColchesterFC]

Why is there such a wide range of prices for the different vaccines? I saw today that the Oxford one was going to be around £2-50 per dose, while the Pfizer one was (I think) around £15 and the Moderna one around £28. Those two might have been the other way around but they were approx the figures given. Is that just the drug companies setting the price or is there more to it than that?

 

[williamalex1]

Probably depends if a government official has shares in the company

 

[Ethan]

Why is there such a wide range of prices for the different vaccines? I saw today that the Oxford one was going to be around £2-50 per dose, while the Pfizer one was (I think) around £15 and the Moderna one around £28. Those two might have been the other way around but they were approx the figures given. Is that just the drug companies setting the price or is there more to it than that?

The Oxford vaccine is a simpler mechanism so can be made in the same factories that other vaccine are made in, so is cheaper. The Moderna and Pfizer are pretty cutting edge and require new manufacturing and expensive ingredients. Pfizer already has loads of manufacturing, Moderna doesn't, so needed to set up manufacturing deals with specialist companies.

US pharmaceuticals tend to have high list prices because their main purchasers, the big insurance companies or Medicare, demand massive discounts, so the real price paid is usually a lot less. The US Govt won't be paying Pfizer £15 a shot. Bulk purchase also reduces price further. I hear that the EU will get Moderna at a much lower price than the UK because they moved faster, this securing some funding for Moderna, and are buying a lot.

The interesting twist will be if the Oxford results are not as strong as Moderna/Pfizer, and I think that is very possible. Then value becomes a consideration. It is worth vaccinating everybody. GPs are being offered £13 to administer both shots.

If every person in the UK, 68 million, got both shots of Pfizer, at £15 per and the GP fee (although not everyone will get it, and not all at GPs), then 67 M x (2 x 15 plus 13) is a total cost of £2.8 billion. That is less than 10% of Rishi Sunak's furlough bill. Now, in practice, the cost will not be that, because the real price will be lower, there will be a mix of cheaper vaccines as well as Pfizer, and some will get it at work (NHS/care home) or not get it at all, but as a major fix for this, it seems like value.

 

[ColchesterFC]

Thanks for the explanation Ethan. ?