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

FMMM1 said:
@Snow Leopard @Jonathan Edwards rumour mill is that the UK will approve the Oxford vaccine (on 28th December). Is there a phase 3 trial ongoing in the US on this vaccine?
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AstraZeneca claimed at the end of November that there were ongoing trials in US, Japan, Russia, South Africa, Kenya and Latin America.

I personally wouldn't approve it as for many people vaccine choice will be either-or and the AstraZeneca vaccine has substantially inferior efficacy, such that using it will require 20-30% more of the population to be vaccinated to achieve herd immunity compared to the two mRNA vaccines.

Notably, for drug approval, subsequently developed drugs generally have to prove they have at least equivalent efficacy/safety to be worthwhile.
 
Following on from my previous post:

"Modelling of COVID-19 vaccination strategies and herd immunity, in scenarios of limited and full vaccine supply in NSW, Australia" 19th december
https://www.medrxiv.org/content/10.1101/2020.12.15.20248278v2

Herd immunity can only be achieved with mass vaccination. With 90% VE, herd immunity can be achieved by vaccinating 66% of the population. A vaccine with less than 70% VE cannot achieve herd immunity and will result in ongoing risk of outbreaks. For mass vaccination, distributing at least 60,000 doses per day is required to achieve control. Slower rates of vaccination will result in the population living with COVID-19 longer, and higher cases and deaths.
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The bold claim is why the AstraZeneca data is currently problematic.
 
With the Pfizer and Moderna vaccines, I heard Vincent Rancaniello (TWIV microbe TV virology podcasts) say that 75% of the population needs to get the vaccine for herd immunity to occur.
 
shak8 said:
With the Pfizer and Moderna vaccines, I heard Vincent Rancaniello (TWIV microbe TV virology podcasts) say that 75% of the population needs to get the vaccine for herd immunity to occur.
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It all depends on the assumptions about transmissibility and network behaviour. If the Pfizer/Moderna vaccines need 75% to be vaccinated, then it is even more likely that choosing to use the AstraZeneca vaccine over the alternatives is a big mistake.
 
Snow Leopard said:
It all depends on the assumptions about transmissibility and network behaviour. If the Pfizer/Moderna vaccines need 75% to be vaccinated, then it is even more likely that choosing to use the AstraZeneca vaccine over the alternatives is a big mistake.
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Thank you @Snow Leopard if the new variant has higher transmissibility (OK that's disputed) then the vaccine may need to be more effective i.e. to achieve herd immunity.
 
chrisb said:
That may depend on the amount of wastage. There have already been two reports that I have seen of refrigeration failure leading to loss of product.
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Loss of product has nothing to do with number needed to vaccinate for a given threshold of "herd immunity".

BurnA said:
I agree with what you are saying but what about countries which won't get either the Moderna or BioNtech vaccines next year, would they be better off having a less effective AZN vaccine?
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In the long run, they'd be worse off. There are going to be more vaccines available next year that may also have superior efficacy. All the claims that poor countries deserve an inferior vaccine because it is a little cheaper just make me feel quite angry.

If anyone wants to use the AZD1222 vaccine, they'd have to have a good reason to do it right now, e.g. vaccinating healthcare workers right now, or selective ring-vaccination. I don't think the general population should be vaccinated with a clearly inferior vaccine.
 
BurnA said:
BBC News - New coronavirus variant: What do we know?
https://www.bbc.co.uk/news/health-55388846

In this BBC article it states
"Studies by the same group suggest the deletion makes antibodies from the blood of survivors less effective at attacking the virus", with a link to paper they released.

Later in the article they ask will the vaccines work against the new variant and the answer is "almost certainly yes, at least for now" and then they conclude with:

A presentation by Prof David Robertson, from the University of Glasgow on Friday, concluded: "The virus will probably be able to generate vaccine escape mutants."

So it's not very clear to me what effect this variant will have on vaccines. Is it fair to say they just don't know yet?
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Bloody hell this is dystopian stuff!
 
Sarah94 said:
https://amp.theguardian.com/world/2...dy?CMP=share_btn_tw&__twitter_impression=true

Thoughts on this @Jonathan Edwards @Snow Leopard ? It's really scary stuff!
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My reaction would be that this was obviously the situation anyway, even if there was no new variant. The level of spread has been allowed to rise such that we are bound to have more deaths next year than this unless there is complete lockdown for a couple of months.

Everyone seems to have been living a fantasy watching the figures rise.

The relevance of the new strain is just that people will have to do things properly to get levels down like last May. All flights need to be cancelled. There need to be bans on moving from county to county except for food delivery and so on. Schools must stay closed. It can be done but people need to get real.
 
I think I read somewhere (can't remember where) that the new variant spreads more easily because less viral load is needed to get ill? Is that true???
 
Sarah94 said:
I think I read somewhere (can't remember where) that the new variant spreads more easily because less viral load is needed to get ill? Is that true???
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I don't think anyone knows yet.

An important thing to remember is that if the faster spread of the new variant is due to something easily avoided - like talking to people without a mask or touching plates and glasses and not washing hands then if people are careful and avoid these things the new variant will spread no faster than the old one.
 
Jonathan Edwards said:
I don't think anyone knows yet.

An important thing to remember is that if the faster spread of the new variant is due to something easily avoided - like talking to people without a mask or touching plates and glasses and not washing hands then if people are careful and avoid these things the new variant will spread no faster than the old one.
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Thanks
 
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