The biology of coronavirus COVID-19 - including research and treatments

horrified to see the number of holiday adverts appearing on the TV, particularly RYanairs 'jab and go' one.

https://metro.co.uk/2020/12/28/ryan...-and-go-after-getting-covid-vaccine-13815697/

 

I wonder if it reflects the fact that the UK has lost control of the virus; therefore, they're forced to act.

 

https://twitter.com/user/status/1344180361811513348

 

LOL

https://www.rte.ie/news/coronavirus/2020/1230/1186937-vaccine-covid/

 

It's politics, because they're suggesting 12 weeks for Pfizer too (which is a mistake in my opinion - the optimum timing is based on germinal centre formation kinetics).

Efficacy for 1 dose of Chadox is around 53% (against disease and significantly lower against asymptomatic infection). (see for 53% claim https://www.gov.uk/government/publi...professionals-on-covid-19-vaccine-astrazeneca)

The modelling of herd immunity is here:
https://www.medrxiv.org/content/10.1101/2020.12.15.20248278v2

Notably, the primary author has been an (independent) paid consultant for AstraZeneca, yet has stated in Australian media "early data suggested it might not be enough to reach “herd immunity” and was not as efficacious as other vaccines."

https://www.afr.com/politics/federa...o-heavily-on-too-few-vaccines-20201218-p56os7

 

This NHS web page says 21 days interval between doses for Pfizer, though very woolly about implications of longer interval.

 

From @Snow Leopard's post and link, it is saying that anything less than 70% efficacy cannot achieve herd immunity. Presumably this efficacy herd immunity threshold will differ depending on disease and its growth rate? If so, does that mean that the new variant of Covid 19, with its significantly faster growth rate, would need a higher efficacy in order to reach herd immunity? Or am I wrong about the growth rate influencing this? My maths is not up to it, but it feels like growth rate would be a factor.

https://www.medrxiv.org/content/10.1101/2020.12.15.20248278v2.full-text

 

The policy seems to be more about reducing the immediate pressure on the NHS than achieving herd immunity in the general population in the shorter term:

https://www.ox.ac.uk/news/2020-12-3...atory-emergency-use-authorisation-coronavirus

 

There is also this information on the Oxford site:

https://www.research.ox.ac.uk/Article/2020-12-30-oxford-vaccine-regulatory-faq

 

[my bold]

How is the efficacy determined? Is it saying that the 70.4% developed no symptoms? And that the 29.6% developed symptoms but none too seriously? So maybe the 29.4% end up more in the situation of people who develop flu, get annoying symptoms but not serious?

ETA: I guess that's what it is saying. If no serious cases then I am much more in favour of this vaccine, insomuch that it can save lives, even if the herd immunity issue is compromised. Saving people needing to go into hospital is major advance.

 

So i was attempting to explain to my carer today that the AZ vaccine had much lower efficacy than Pfizer.... she didnt believe me said 'it cant be they wouldnt have authorised it'
<sigh>
i said i would get proof....
i looked on your link @Snow Leopard

but i couldnt make it out, sorry to be so dense - I looked at the table but i cant see where it says 53%
If you have time could you point out to me where it says it so i cant point it out to her.

I am also confused because i thought the better efficacy was from giving a 1/2 dose & then a full dose later - something that was discovered through some kind of error/serendipitous event... but the MHRA have authorised 2 full doses....
eh??? that doesnt seem to make sense what am i missing.

Also can someone tell me what the downside might be on a personal level to having the AZ over pfizer, beyond being less well protected... ie is it better to have 53% protection than no protection at all?

 

I am not sure but I don't think it's correct to say 53% protection. It would be a 53% chance of protection.
In other words toss of a coin whether you have protection or not, if you get the Oxford vaccine.

Edit: actually I think the figure is 62%
Edit Edit: 62% for both full doses.

 

I agree completely, i wasnt trying to pursuade, she is very pro all vaccines so no issue there, i was explaining why i wished i would get the pfizer one (which i would have had i been 95 & 1st in the queue). I wanted to prove my reasoning because she is older generation & is suspicious of any information that does not come through BBC TV news... When i say i have been discussing/listening to scientists in an online forum she hears 'a bunch of nutters on facebook' lol. She hasnt said this outright but she is always sceptical of anything i say that i got online unless i say i read it on the BBC... lol & even then...

In the main her attitude is healthy but if i choose not to get the AZ vaccine, or to get it & still continue making her wear an uncomfortable FFP3 mask, i want to be able to back it up with facts that i can prove, otherwise i will get "if you had the vaccine/trusted the vaccine, you wouldnt have to take all these hypervigilant precautions"

 

I think we are all going to need to continue with full preventive measures whether or not we have either vaccine. That is certainly the case for the Oxford vaccine and there is no guarantee that the Pfizer vaccine will be quite so good in practice in a UK context.

When people talk of a useful degree of herd immunity I see that as a helping factor in getting the epidemic recede while taking full precautionary measures. Without precautionary measures almost everyone has to be immune to stop spread continuing.

 

Just to say, I don't think this is the case. 70% was the average between the full dose regimen and the half initial dose. It's a made up figure with no practical use. Either someone gets the full dose and they have about a 62% chance of protection or they get the half initial dose and it's closer to 90%.
But the half initial dose regimen has not been approved yet AFAIK.

This is my interpretation but I have been trying to figure it out so I could be wrong.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)32623-4/fulltext

 

So wait. This is giving me a headache.

When Pfizer was rolled out, second dose was supposed to be 3 weeks after the initial dose.

but now they’ve said yes to AZ, and with that one, it can be given 12 weeks after.

So now they’ve also said the Pfizer one can be given 12 weeks after? Even though there’s no research about that? And there’s nothing about safety or efficacy?

And with AZ, the half dose is more effective (based on a small sample, I was only able to half follow the thread), but yet they’re giving people the initial full dose then another full dose? At a very low efficacy compared to what we could have got from other vaccines potentially?

Do they even know if it’s safe to then give people vaccines after. Like what if a really good vaccine comes up in the next few months, do they know it’ll be safe to give them that after giving everyone the AZ and Pfizer? Or are we just stuck with what we’ve already had?

AND, do they know it won’t actually stop people spreading it? What if people have the vaccine, don’t have symptoms but can still spread it and shed the virus, thereby infecting lots of people inc vulnerable people without realising? Because they think they’re safe. Or, because they think they’re safe, what if they start to take risks and reduce mask wearing, which will surely happen. Has human behaviour even been thought about?

This is really stressing me out.

 

Stats is my weakness, but the confidence intervals for astra zeneca are concerning compared to Pfizer/ Moderna .

Wide is an understatement - relying on this to gain herd immunity looks like wishful thinking.

It does offer market share before others are approved . ...

 

You can tell her that protection from the vaccine isn’t anywhere close to 100%, which means that if there’s even a small chance she’s carrying it - then if she doesn’t wear a mask - she will pass it on to you. And due to your existing conditions and already being very ill, you may not be able to recover from it. So she will need to continue wearing a mask and practicing all her usual hygiene issues until the virus has actually been eradicated. You need to remain safe.

Also that even if she is protected from the virus and doesn’t show symptoms, there is no research to say that she’s not shedding it or passing it on (as far as I know), so there’s a risk from that too.

This is what I would say. I said it to my boyfriend the other day, because he was getting excited about the vaccine and coming to see me, and I said, you would still have to wear a boiler suit and FFP2 / FFP3 mask if you’re coming in after a vaccine I’m afraid. (And I would still be very stressed!)