Question about covid vaccine trials

[studiot]

For each of the vaccines being developed some tens of thousands of volunteers have received the vaccine.

From what I understand about 50% received a placebo.

As some of the vaccines are now being licenced and in production,

What happens to those who had the trial version and what happens to those who had the placebo but did not contract the virus ?

[iNow]

The vaccine would be available to them subject to local prioritization just like the rest of us 

[MigL]

You guys in the UK have already approved the Pfizer/BNT vaccine for emergency use, haven't you ?
The US is close to granting approval, and we, in Canada, may be a couple of weeks behind.

[CharonY]

1 hour ago, MigL said:

The US is close to granting approval, and we, in Canada, may be a couple of weeks behind.

I think about 10 days is what I read. 

[studiot]

I am sorry ladies and gentlemen, but none of this addresses my query.
Perhaps I did not make myself properly clear.

 

If you are one of the thousands who have taken part in the vaccine trial.

1) On what basis should you decide whether to have another shot ?

2) Would any of the available vaccines be licenced for someone who has already had a shot ?

3) Would it be advisable to have have the same vaccine or a different one ?

4) Would it be safe to have another shot whether or not you actually reveived the trial vaccine ?

These questions should be considered in the light of the fact that roughly half the trialists had a placebo and were not actually vaccinated but do not know if they received the vaccine or the placebo.

These are serious questions I had not thought of before, but arose because I know someone who took part in one of the covid trials and now needs to know whether to have another vaccine.

Of course this would apply to any new vaccine reaches further than Covid.
Thre must be a procedure, though I have not thought about it before so I am asking the question.

 

[Bufofrog]

1 hour ago, studiot said:

I am sorry ladies and gentlemen, but none of this addresses my query.
Perhaps I did not make myself properly clear.

 

If you are one of the thousands who have taken part in the vaccine trial.

1) On what basis should you decide whether to have another shot ?

2) Would any of the available vaccines be licenced for someone who has already had a shot ?

3) Would it be advisable to have have the same vaccine or a different one ?

4) Would it be safe to have another shot whether or not you actually reveived the trial vaccine ?

These questions should be considered in the light of the fact that roughly half the trialists had a placebo and were not actually vaccinated but do not know if they received the vaccine or the placebo.

These are serious questions I had not thought of before, but arose because I know someone who took part in one of the covid trials and now needs to know whether to have another vaccine.

Of course this would apply to any new vaccine reaches further than Covid.
Thre must be a procedure, though I have not thought about it before so I am asking the question.

 

I believe this answers your question, at least with the Pfizer vaccine.

https://www.statnews.com/2020/11/12/pfizer-says-placebo-patients-will-eventually-get-its-covid-19-vaccine-the-question-of-when-is-complicated/

[dimreepr]

2 hours ago, studiot said:

These questions should be considered in the light of the fact that roughly half the trialists had a placebo and were not actually vaccinated but do not know if they received the vaccine or the placebo.

When the trials are published, why wouldn't they know?

[iNow]

41 minutes ago, dimreepr said:

When the trials are published, why wouldn't they know?

Publications show numbers and percentages, but not lists of names of study participants nor which study group into which they were assigned. Participants also are not generally told which group they were part of when studies conclude. 

3 hours ago, studiot said:

3) Would it be advisable to have have the same vaccine or a different one ?

4) Would it be safe to have another shot whether or not you actually reveived the trial vaccine ?

I’m struggling to conceive of a reason why receiving a second dose would pose any risk given the way vaccines work. There’s no big issue with toxicity or interaction. If you got a flu shot in October and another in December, the biggest risk is a bruise or extra poke on your arm. One imagines covid vaccines would be similar. 

[MigL]

Sorry for misunderstanding Studiot.

Further to what INow has said, all the leading vaccines work by 'engineering' protein sequences onto the corona spikes of a 'dummy' virus or sterile ( cannot reproduce ) virus. These 'engineered' spikes mimic those of CoV2, and stimulate a response from the host's immune system either in the way of anti-bodies, or 'remembering' and producing the required anti-bodies.
Any further introduction of the vaccine would be equivalent to a booster, and should have no adverse effects over the original.

Maybe CharonY can elaborate further, but I would think that if these vaccines work as intended, this would mean no further worries about any coronaviruses. As soon as the new virus ( SARS, MERS, SARS-CoV2, etc ) is sequenced, the new protein configuration is 'engineered' onto the spikes, with resultant immunity. I believe the work at Oxford was started during the MERS outbreak, and modified quickly for use against CoV2.

At least, that is my simplistic take on the matter.
 

[studiot]

3 hours ago, Bufofrog said:

5 hours ago, studiot said:

 

I believe this answers your question, at least with the Pfizer vaccine.

Thanks  +1

 

2 hours ago, iNow said:

I’m struggling to conceive of a reason why receiving a second dose would pose any risk given the way vaccines work. There’s no big issue with toxicity or interaction. If you got a flu shot in October and another in December, the biggest risk is a bruise or extra poke on your arm. One imagines covid vaccines would be similar. 

Firstly there is a difference between the first and second doses for at least some of the vaccines, notably the Sputnik and Astra - Zeneca 'Oxford' vaccine.

Secondly the mistake made with the Oxford study confirms that the vaccine is less effective if you get the wrong dose on the second shot, let alone the the logistic issue of what would happen if you got the second shot from the wrong vaccine.

Thirdly there have been no studies to my knowledge of possible interactions between different vaccines.

The rule in the UK is that you cannnot have a covid vaccination within 3 weeks of the annual flu jab.

[CharonY]

3 hours ago, dimreepr said:

When the trials are published, why wouldn't they know?

No, these types of trials are often kind of open ended. The idea is to collect efficacy data for as long as possible and you need the placebo group as a comparison. Even when a drug is approved, folks like to continue to collect data as it can tell you e.g. whether there may be problems in certain folks that do not show up immediately or in case of vaccines to see how long they are protective. If you tell folks that they are in the placebo group or vaccinate them, the ability for comparison is gone. Especially as this trial is unusually short, they may want to keep going even after emergency approval. It will depend a bit on what type of consent form the participants signed, whether they can do so.

 

1 hour ago, MigL said:

Maybe CharonY can elaborate further, but I would think that if these vaccines work as intended, this would mean no further worries about any coronaviruses.

The "if they work as intended" is a big if. mRNA based vaccines were not considered a very efficient route as most data suggested low efficacy. The results of the current vaccines are extremely surprising to about everyone (in a positive way), but there is no guarantee that it will be true for any other related vaccination. We also still do not know how long the protection lasts. So, personally I would still be very worried about about future outbreaks.

I will also add that complacency is what ultimately leads us into poor responses to diseases and as well as other challenges (e.g. global warming). Having more tools at hand is great, but without having safeguards and prevention measures in place, they will only reduce damages (to some degree) but will not protect us.

These challenges are a team sport and there are no silver bullets that can save us if we screw up. This pandemic is (yet) another test run for what is to come. And by most measures we did poorly.

[MigL]

2 hours ago, studiot said:

Secondly the mistake made with the Oxford study confirms that the vaccine is less effective if you get the wrong dose on the second shot, let alone the the logistic issue of what would happen if you got the second shot from the wrong vaccine.

Again I defer to CharonY's expertise on the matter, but it was the first dose which was in question with the Oxford study.
As these vaccines are meant to trigger a response from the host's immune system, an 'overreaction' is sometimes a bad thing ( see Cytokine storm ).
Maybe the half initial dose produces a more favorable reaction from the immune system, without overloading it, and 'primes' it to better 'remember' the proper response when the second full dose is introduced. Kind of like a 'warm-up' for the immune system.

Also not 100% sure, but the vaccine 'mimics' the spikes of CoV2 to produce an immune system response in the host.
IOW, the different spikes produce are designed to produce the same result.
I would think, then, that any/all spikes which produce that result, will work as a booster.

Edited December 5, 2020 by MigL

[CharonY]

On 12/5/2020 at 1:08 PM, MigL said:

Maybe the half initial dose produces a more favorable reaction from the immune system, without overloading it, and 'primes' it to better 'remember' the proper response when the second full dose is introduced. Kind of like a 'warm-up' for the immune system.

One of the hypotheses is that the type of delivery resulted in the immune system to react more strongly to the vector, rather than the viral antigen.

Edit: But I should add that we do not know whether the effect is actually really. The accidental application of half doses has split the number of patients further so we only got an even smaller number to draw from. It may very well be a statistical fluke rather than a biological effect.

[CharonY]

On 12/4/2020 at 6:08 PM, studiot said:

For each of the vaccines being developed some tens of thousands of volunteers have received the vaccine.

From what I understand about 50% received a placebo.

As some of the vaccines are now being licenced and in production,

What happens to those who had the trial version and what happens to those who had the placebo but did not contract the virus ?

One should add that this is also an ethical question that as of yet (to my knowledge at least) has not been resolved yet. Especially in long-term studies the placebo group is often not revealed in order to collect data for as long as possible. This, of course leads to an ethical dilemma. On the one hand, participants are informed that they might receive a placebo and, in the case of vaccine trials, might not be protected (though of course, there was no guarantee that the vaccinated group was protected, either). On the other hand, after efficacy is established, one needs to balance the need for data collection with protection of the participants. This is an ongoing discussion in the community and I am not sure where the decision will ultimately land.

[studiot]

3 hours ago, CharonY said:

One should add that this is also an ethical question that as of yet (to my knowledge at least) has not been resolved yet. Especially in long-term studies the placebo group is often not revealed in order to collect data for as long as possible. This, of course leads to an ethical dilemma. On the one hand, participants are informed that they might receive a placebo and, in the case of vaccine trials, might not be protected (though of course, there was no guarantee that the vaccinated group was protected, either). On the other hand, after efficacy is established, one needs to balance the need for data collection with protection of the participants. This is an ongoing discussion in the community and I am not sure where the decision will ultimately land.

 

 

We know the details were uncovered for this lady.

 

https://www.bbc.co.uk/news/blogs-trending-55179300

[CharonY]

1 hour ago, studiot said:

 

 

We know the details were uncovered for this lady.

 

https://www.bbc.co.uk/news/blogs-trending-55179300

In cases of complications patients often get unblinded as it can inform on treatment of the patient.