Risky business?

[johnnyrod]

Yes but how long is protection afforded from one or two doses?

[DJ123]

Originally Posted by Red Herring

There is actually logical argument behind the proposal, not just political gain.

In trials the Pfizer vaccine was found to be 90% effective after the first dose and this improved to 94% after the second.

So given it takes the same amount of clinical time to administer each dose would you rather have a number of people protected to 94%, or twice as many protected to only 90%?

I'd suggest at those odds it might be worth considering......

Seeing as this first lot is for the most vulnerable, the more the better IMO. These are the people you're trying to protect the most, you need to minimise the risk as much as possible and have the option to do so.
If it was a general one for all, then i'd say 90% is probably enough.

[embee]

Originally Posted by Red Herring

....In trials the Pfizer vaccine was found to be 90% effective after the first dose and this improved to 94% after the second.....

Well, there are different reports it would appear. The BMJ, a reasonably reputable publication, would suggest different numbers (published 11th Dec 2020) https://www.bmj.com/content/371/bmj.m4826
If as shown the Pfizer vaccine is only 52% effective after the first dose and 95% after the second, it would seem somewhat cavalier to suggest a significant delay of administering the second dose beyond the originally recommended 21days. I'm not aware that Pfizer have condoned the extension yet.
The USA authority CDC are still specifying an interval of 21days +/-4 days between doses (as of 30th Dec) https://www.cdc.gov/vaccines/covid-1...derations.html

I'm suspicious of the vaccination rates being bandied about. If as suggested it ramps up to 2m per week but the interval is extended to 12 weeks, which conveniently takes us pretty much to Easter to achieve the 20million highest priority subjects which is the Government gateway claim currently being offered, then the second doses would have to start being administered at the same 2m/week rate after that. If the total rate hasn't increased substantially by then (and I doubt it will, but we'll see), then there will be no further NEW recipients for a further 10 weeks until all the second doses are completed. I think there'll be a class1 smoke and mirrors exercise at the briefings to hide the reality ............. until it's too late. I hope as usual that I'm wrong. If I'm not wrong, I can look forward to getting a vaccine sometime late summer.

[Seeker]

yet more guesswork from BoZo's Performing Clowns:

https://www.businessinsider.com/uk-m...21-1?r=US&IR=T

I'm assuming they're taking advice from the guy that was in charge of Woolworth's Pic'n'Mix department.

Does anyone trust these people?

[Biker Biggles]

Originally Posted by Red Herring

There is actually logical argument behind the proposal, not just political gain.

In trials the Pfizer vaccine was found to be 90% effective after the first dose and this improved to 94% after the second.

So given it takes the same amount of clinical time to administer each dose would you rather have a number of people protected to 94%, or twice as many protected to only 90%?

I'd suggest at those odds it might be worth considering......

Leaving aside issues with the use of statistics and data-------

That argument would suggest we dont need to bother with the second dose at all but Im not sure there is a study yet which shows sustained effectiveness from one dose. Perhaps there is current research going on into that but in the meantime I think we should be guided by the advice of the manufacturers. Incidently, if we dont give the second dose to the initial Pfizer recipients it seems likely we will have difficulty obtaining supplies in two or three months as they become due so the policy decision will have been made for us?
My fear is that short term political factors will overide scientific knowledge and we will see an endless cycle of new waves of infection as vaccine effectiveness wears off every six to twelve months because we didnt do the job properly.

[garynortheast]

Originally Posted by Seeker

yet more guesswork from BoZo's Performing Clowns:

https://www.businessinsider.com/uk-m...21-1?r=US&IR=T

I'm assuming they're taking advice from the guy that was in charge of Woolworth's Pic'n'Mix department.

Does anyone trust these people?

Nope.

[Red Herring]

Originally Posted by embee

Well, there are different reports it would appear. The BMJ, a reasonably reputable publication, would suggest different numbers (published 11th Dec 2020) https://www.bmj.com/content/371/bmj.m4826
If as shown the Pfizer vaccine is only 52% effective after the first dose and 95% after the second, it would seem somewhat cavalier to suggest a significant delay of administering the second dose beyond the originally recommended 21days. I'm not aware that Pfizer have condoned the extension yet.
The USA authority CDC are still specifying an interval of 21days +/-4 days between doses (as of 30th Dec) https://www.cdc.gov/vaccines/covid-1...derations.html

I'm suspicious of the vaccination rates being bandied about. If as suggested it ramps up to 2m per week but the interval is extended to 12 weeks, which conveniently takes us pretty much to Easter to achieve the 20million highest priority subjects which is the Government gateway claim currently being offered, then the second doses would have to start being administered at the same 2m/week rate after that. If the total rate hasn't increased substantially by then (and I doubt it will, but we'll see), then there will be no further NEW recipients for a further 10 weeks until all the second doses are completed. I think there'll be a class1 smoke and mirrors exercise at the briefings to hide the reality ............. until it's too late. I hope as usual that I'm wrong. If I'm not wrong, I can look forward to getting a vaccine sometime late summer.

Some very good points well made.

Statistics are always a bit dodgy, especially when they involve something as unreliable and unpredictable as medicine......

Referring just to the paper published in the BMJ as Embee has shared it here...

One of the biggest issues raised around the efficacy of the vaccine after just the one dose was just how "sterile" were the subject group. Finding 43k people to take part in the study who had all been self isolating for two weeks would have been impossible (especially if you wanted the group to be representative of a population with regard to age/sex/ethnic background etc...) so you have to factor in that a percentage of those receiving the first dose may have already been infected, or indeed become infected post vaccination and before they had developed immunity. Obviously by the time you come to administer the second booster dose your subject group will be far less likely to already been carrying a Covid infection (on account of the first dose) so you need to consider this when analysing results......

What is particularly important is the instance of serious Covid cases after just the first dose. There were thirty nine cases of Covid within the subject group (some 21,700 people) with only one of these being classified as serious. In the similar sized placebo group there were 82 cases of Covid (hence the 52% efficacy figure) but of these nine were classified as serious. In essence this is saying that after a single dose you are half as likely to catch Covid but nine times less likely to develop serious symptoms.

Given that it is those with serious symptoms that are going to bring the NHS to it's knees (or die......) I can still see why they are driving administering just the single dose.

[SV650rules]

Originally Posted by Red Herring

There is actually logical argument behind the proposal, not just political gain.

In trials the Pfizer vaccine was found to be 90% effective after the first dose and this improved to 94% after the second.

So given it takes the same amount of clinical time to administer each dose would you rather have a number of people protected to 94%, or twice as many protected to only 90%?

I'd suggest at those odds it might be worth considering......

Agree, The vaccine makers did do a single dose during trials and found that nobody who had single dose got sick enough to need hospital treatment. They said a good level of immunity 14 to 20 days after jab. Another thing is that ultra low temperature storage needed for Pfizer vaccine is in short supply, so rather than having to keep vaccine for second doses and at same time have to store newly arrived doses as well, it is better to use vaccine ASAP rather than keep it stored doing no one any good.

[Seeker]

but most people in the UK will get the AstraZeneca vaccine and the MHRA only approved it for a 2 dose regime.
https://www.sciencemediacentre.org/e...k-by-the-mhra/

There are still questions on the AZ's efficacy since the testing had dosage errors.

Regarding the one dose plan, one GP surgery said they'd given 1600 people the first injection and now had to call the 1600 to cancel the second jab plus call another 1600 to schedule a first for which they didn't have the staff. Another surgery said they'd stick to the 21 days separation and defy the recommendations. I have no faith that Hancock knows what he's doing. All that's missing is him running around shouting: "Don't Panic" to complete the farce.

[SV650rules]

Makes more sense to vaccinate 2 million people a week with a dose that will prevent them being sick enough to need hospital care than to vaccinate half that number and tie up the scarce low temperature freezer space. Looks like experts in USA may take the British approach, as Churchill said 'America will normally make the right decision, but only after they have exhausted all other possibilities'...

I read a report on test done on a single dose of Oxford / AZ vaccine trials that said within 14 to 20 days a good level of immunity was given, the second dose is a booster, to try to ensure immunity lasts for a longer time.
If the mutations of virus continue an new vaccine may be needed anyway and the second shot of original vaccine may have been wasted.

https://thehill.com/policy/healthcar...d-vaccinations

Originally Posted by Red Herring

What is particularly important is the instance of serious Covid cases after just the first dose. There were thirty nine cases of Covid within the subject group (some 21,700 people) with only one of these being classified as serious. In the similar sized placebo group there were 82 cases of Covid (hence the 52% efficacy figure) but of these nine were classified as serious. In essence this is saying that after a single dose you are half as likely to catch Covid but nine times less likely to develop serious symptoms.

Given that it is those with serious symptoms that are going to bring the NHS to it's knees (or die......) I can still see why they are driving administering just the single dose.