Second vaccine dose timing

Having had my first dose of the Pfizer vaccine two weeks ago, I do not intend to change my ultra-cautious behaviour until at least three weeks after my second dose, which I hope I will get within the next ten weeks as promised.

Although I was impressed with the efficient organisation of our vaccinations, no-one told me that.

I think that when waiting for fifteen minutes after vaccination we should be clearly instructed to keep vigilant until at least three weeks after the second dose. Although we may have some measure of protection from the first dose, we could put others at risk by taking risks ourselves, so we need to minimise contacts, keep our distance and wear a mask.

Actually after re-reading I see I have got that wrong - its not just against the E484K mutation.

Always happy to admit when I make a mistake :-). Still don't think they should change the dosing schedule yet though.

Oops - cross-post Rosie51

Alegrias1 I still think they should do everything possible to protect the 50% of over 80s who won't have sufficient protection after one dose, when 100% of them did after the second dose. How many are going to add to our death toll quite unnecessarily?

Rosie51 ( and anyone else)- I absolutely understand your concern, however the primary weakness of this research is the small sample size, and the use of the word median - half of the 23 subjects were under the age of 80.

This might sound like pedantry but what it means is that the result of this research is not generalisable to the whole population. The only thing this research tells us is that the topic needs more research before it can be deemed fact and that the major indicator is that vaccine developers will need to anticipate mutations and variants.

As a piece of quantitative research it's not robust enough to standalone and needs to be supported by further research. It really shouldn't be used as evidence of anything other than the need for more study with a larger sample and more attention to the variables.

I agree that the over 80's should have the full dose ASAP - my agreement is moral. There is just not enough science (yet) to support it on any other level.

NellG, I do understand the limitations of the research, (background many, many years ago in statistics), but as there can be no harm in sticking to the timetable the manufacturers recorded their data from, and possibly harm from deviating wildly from this, I have to support shortening the 12 week gap, and not just on moral grounds. I note that much of Europe is stating there's not the scientific evidence to confirm the AZ vaccine is suitable for over 65s and some are saying younger than that. Our interpretation of the data seems to be at odds with theirs. Same science, different conclusions.

Rosie51 I note that you are a statistician so I have a bit of reluctance in putting this forward, but here goes anyway....

Let's assume that the figures are about right and you only get 50% protection with the first dose, even though as NellG says the figures are far from robust. Pfizer claim about 90% after 2 doses.

So say you have 10,000 people and 10,000 doses to distribute among them. The options are that everybody gets one dose and has to wait 12 weeks for the next, or 5,000 people get two doses within 3 weeks.

I don't know what the chance of getting Covid is for unvaccinated over 80s, but lets say 1% because its easy to calculate. Its probably much less than that.

Then with the one dose option 50 people get Covid within the 12 weeks. (10,000 people with 50% protection) With the two dose option 55 people get Covid within the next 12 weeks. (5000 people with 90% protection and 5000 with none at all.) That's a 10% increase and scales up to large numbers.

Now I know its more complicated than that and that more doses are coming available all the time, and the powers that be have better models than me with a spreadsheet, but I can understand why the decisions have been taken on public health grounds.

The thing with the AZ vaccine and over 65s is a weird one. Not sure I entirely understand it, but I believe it was to do with second level research exploring dosage and dosage interval rather than the first level efficacy and safety research. For some reason they did not include over 65s in the study, therefore their findings weren't applied to that group - not because there is no evidence that it works, but because it would be unethical to pretend that group was included in the study. Equally, the results are generalisable to that group, so there is no evidence that they are adversely affected by dose/interval. I'll try to go back and find the evidence for that and post the link.

Here's an article that explains things quite well.

blogs.sciencemag.org/pipeline/archives/2020/11/23/oxford-az-vaccine-efficacy-data

Bringing an old thread back to life....

Researchers publish a paper in the New England Journal of Medicine with data that supports the longer dosing interval for the Pfizer vaccine and urging the US to adopt this to save thousands of COVID-19–related hospitalizations and deaths this winter in the United States

www.nejm.org/doi/full/10.1056/NEJMc2036242

Alegrias1

Bringing an old thread back to life....

Researchers publish a paper in the New England Journal of Medicine with data that supports the longer dosing interval for the Pfizer vaccine and urging the US to adopt this to save thousands of COVID-19–related hospitalizations and deaths this winter in the United States

www.nejm.org/doi/full/10.1056/NEJMc2036242

I’m not getting this - where’s the data on a gap longer than 2/3 weeks as opposed to a theoretical derivation?

I'm not even going to get into this conversation, because I know your background suzie and I expect you could run rings round me. But this shows that there are scientists in countries other that the UK who are saying that the longer dose with Pfizer is the right way to go.

So we can maybe put a halt to the idea that the government are doing it for Brownie points?

Alegrias1

I'm not even going to get into this conversation, because I know your background suzie and I expect you could run rings round me. But this shows that there are scientists in countries other that the UK who are saying that the longer dose with Pfizer is the right way to go.

So we can maybe put a halt to the idea that the government are doing it for Brownie points?

Don’t be like that - I accept the idea that a longer dosing interval has much merit and especially in a country where infection levels are still high. But I don’t accept this argument being wrapped up and presented as based on anything other than a theoretical derivation no matter how well founded.

I'm not being funny - I just know not to get into an argument I'd lose.

But I am heartily fed up of the notion that it was the government who made this decision in order to improve their ratings when there was a very good scientific rationale for doing it. And this paper seems to reinforce that decision, and its not UK based.

Alegrias1

I'm not being funny - I just know not to get into an argument I'd lose.

But I am heartily fed up of the notion that it was the government who made this decision in order to improve their ratings when there was a very good scientific rationale for doing it. And this paper seems to reinforce that decision, and its not UK based.

I’ve never thought that - I thought they did it because we were in a right mess and it was the least worst option. It doesn’t make it an evidence based decision but one based on necessity rooted in sound theory. If we start making data and theory interchangeable, why bother with research at all? Yes I know that’s a bit extreme but you know what I mean.....

Fair enough, I get your point. I shouldn't have used the word "data" in my post this afternoon, I can see what you mean. But there was a good reason for taking the route we did, and it wasn't just to get the government out of a hole or to to let them be able to show what a big number of jabs we've delivered. I think it's the right decision and now we're seeing other academics support it.

I've also seen a WHO person say it was the right decision too, but I haven't posted that because the WHO aren't so popular on here, especially the person who said it!

Agree with all that ?