mrk
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Post by mrk on Nov 16, 2020 12:03:08 GMT
Well, it is about "Potential trajectories for COVID-19 in the next 6 months" so perhaps not surprising they don't mention waning immunity in the longer period. They do mention "this is very different from a classic “herd-immunity” scenario ... potentially leading to a long, relatively flat plateau of relatively high incidence unless measures are further intensified to drive incidence down" and "There will be very limited room to relax interventions, since the absolute level of population immunity reached will likely still be low". The way I read it is they're basically saying: if we cannot have more restrictive measures, at least get the R down to 1.1 or so and the epidemic should gradually plateau (albeit at a high level) without spiralling completely out of control. It's interesting that we can actually estimate the human cost in terms of lives lost (and remember, for the sake of this argument we are ignoring the long term effects of those infected yet survive) to reduce R t. To reduce R t from 1.1 to 1.0 would require a further attack rate of 9% of the population of ~67 mil. The late stage IFR is currently modelled at 0.77% (see here). Therefore, assuming immunity doesn't wane (which there is evidence to the contrary), enhanced treatments don't materialise (which we'd hope is not the case), and a representative proportion of the population are infected (protecting the vulnerable and elderly has failed to date)*, then we're looking at somewhere like 46k dead to achieve an indiscernable reduction in R t. *I'm ignoring the wackos that say those susceptible have already died, and that these are the main, not unreasonable, assumptions. I'm implicitly assuming these infections would take place before a vaccine has been rolled out (remember, after 10 months we still are not regularly testing all healthcare workers and care home residents + staff so what hope have we of rolling out a vaccine in double quick time?). It does seem to me that the government is not really aiming to minimise the number of deaths, it's only willing to step in when the NHS risks being overwhelmed. So it's like they asked their advisers: what's the bare minimum we can do to keep hospitalisations within the NHS capacity? Perhaps that's even understandable given the growing resistance against stricter restrictions. But of course it didn't have to be like this, we're here because the test trace & isolate system failed.
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Post by dan1 on Nov 16, 2020 12:10:49 GMT
It's interesting that we can actually estimate the human cost in terms of lives lost (and remember, for the sake of this argument we are ignoring the long term effects of those infected yet survive) to reduce R t. To reduce R t from 1.1 to 1.0 would require a further attack rate of 9% of the population of ~67 mil. The late stage IFR is currently modelled at 0.77% (see here). Therefore, assuming immunity doesn't wane (which there is evidence to the contrary), enhanced treatments don't materialise (which we'd hope is not the case), and a representative proportion of the population are infected (protecting the vulnerable and elderly has failed to date)*, then we're looking at somewhere like 46k dead to achieve an indiscernable reduction in R t. *I'm ignoring the wackos that say those susceptible have already died, and that these are the main, not unreasonable, assumptions. I'm implicitly assuming these infections would take place before a vaccine has been rolled out (remember, after 10 months we still are not regularly testing all healthcare workers and care home residents + staff so what hope have we of rolling out a vaccine in double quick time?). It does seem to me that the government is not really aiming to minimise the number of deaths, it's only willing to step in when the NHS risks being overwhelmed. So it's like they asked their advisers: what's the bare minimum we can do to keep hospitalisations within the NHS capacity? Perhaps that's even understandable given the growing resistance against stricter restrictions. But of course it didn't have to be like this, we're here because the test trace & isolate system failed. Absolutely, on both points. I would add that this latest "lockdown" was the failure of the policy to try and avoid the NHS being overwhelmed whilst keeping as much open as possible - what makes them think it will work in future (I guess they feel they have no other choice). I would also add that as big as the TTI failure is the failure in public healthe messaging - think Barnard Castle, too little emphasis on ventilation, the "debate" on masks, testing targets (yup, we had unused "capacity" of hundreds of thousands of tests yet people in healthcare/care homes still struggle to get tested regularly). Grrrr....
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ilmoro
Member of DD Central
'Wondering which of the bu***rs to blame, and watching for pigs on the wing.' - Pink Floyd
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Post by ilmoro on Nov 16, 2020 12:14:06 GMT
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agent69
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Post by agent69 on Nov 16, 2020 12:23:38 GMT
The fat boy definitely isn't going to like the timing of this one (albeit the stock market appears happy with the announcement).
However, the 95% is based on 95 people testing positive, which doesn't sound a very big sample. On an encouragng note, of the 95 who tested positive 11 had a severe cases, but all were unvaccinated.
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Post by Ton ⓉⓞⓃ on Nov 16, 2020 12:34:46 GMT
We were being told that there might be many vaccines for covid that weren't any good or had too many or too severe side effects. Whereas we're seeing most(?) of the covid vaccine being incredibly effective. Anyone, why is this?
Name
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| efficacy
| Sputnik V vaccine
| Russia | 92%
| Moderna RNA vaccine | US | 94.5%
| Pfizer and BioNTech SE
| US/German | 90%
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mrk
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Post by mrk on Nov 16, 2020 12:39:45 GMT
The fat boy definitely isn't going to like the timing of this one (albeit the stock market appears happy with the announcement).
However, the 95% is based on 95 people testing positive, which doesn't sound a very big sample. On an encouragng note, of the 95 who tested positive 11 had a severe cases, but all were unvaccinated.
That's how phase 3 trials work. You take say 20,000 volunteers, divide them into 2 groups, give the vaccine to 10,000, give a placebo to the other 10,000, then wait for some to catch Covid-19. Once you have enough data (and 95 is enough to be "statistically significant") you look at how many were in the vaccine group. If the vast majority of those who fell ill had the placebo, then you know the vaccine is effective.
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Post by bracknellboy on Nov 16, 2020 12:42:53 GMT
We were being told that there might be many vaccines for covid that weren't any good or had too many or too severe side effects. Whereas we're seeing most(?) of the covid vaccine being incredibly effective. Anyone, why is this?
I've no idea: but interesting to note that BOTH the Pfizer and Moderna are (m)RNA vaccines as I understand it rather than the more "traditional" ways of producing vaccine.
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IFISAcava
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Post by IFISAcava on Nov 16, 2020 12:47:56 GMT
We were being told that there might be many vaccines for covid that weren't any good or had too many or too severe side effects. Whereas we're seeing most(?) of the covid vaccine being incredibly effective. Anyone, why is this?
Name
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| efficacy
| Sputnik V vaccine
| Russia | 92%
| Moderna RNA vaccine | US | 94.5%
| Pfizer and BioNTech SE
| Row 3 column 2 | 90%
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Because "might" doesn't mean "will probably". And I suppose expectation management. EDIT: And I am not sure there was as much pessimism as you suggest - my recollection is of general optimism about a vaccine, but caution as to how fast it could be developed, In fact, the speed has been faster than expected, sadly probably in part because of the second wave speeding up infection rates enough to get a quick answer.
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Post by bracknellboy on Nov 16, 2020 12:49:05 GMT
The fat boy definitely isn't going to like the timing of this one (albeit the stock market appears happy with the announcement).
However, the 95% is based on 95 people testing positive, which doesn't sound a very big sample. On an encouragng note, of the 95 who tested positive 11 had a severe cases, but all were unvaccinated.
I think the 95 is a pretty standard number for stage 3 trials for the point at which you 'unblind' the trial. Its not the 95 itself which is really important, its whether a) the difference between the 'with placebo' and 'with trial drug' is statistically significant and b) whether the total number is also statistically significant. As I say, I think the 95 and sample size is considered a standard threshold, and in this case I think they said the 95 was split 90/5 between the groups. You don't have to be a statistician to think that is going to be statistically significant.
It is beginning to suggest that there may well be some light at the end of the tunnel. Was the Moderna drug funded by Operation Warp Speed do we know ?
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ilmoro
Member of DD Central
'Wondering which of the bu***rs to blame, and watching for pigs on the wing.' - Pink Floyd
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Post by ilmoro on Nov 16, 2020 12:51:24 GMT
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ilmoro
Member of DD Central
'Wondering which of the bu***rs to blame, and watching for pigs on the wing.' - Pink Floyd
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Post by ilmoro on Nov 16, 2020 12:53:23 GMT
The fat boy definitely isn't going to like the timing of this one (albeit the stock market appears happy with the announcement).
However, the 95% is based on 95 people testing positive, which doesn't sound a very big sample. On an encouragng note, of the 95 who tested positive 11 had a severe cases, but all were unvaccinated.
I think the 95 is a pretty standard number for stage 3 trials for the point at which you 'unblind' the trial. Its not the 95 itself which is really important, its whether a) the difference between the 'with placebo' and 'with trial drug' is statistically significant and b) whether the total number is also statistically significant. As I say, I think the 95 and sample size is considered a standard threshold, and in this case I think they said the 95 was split 90/5 between the groups. You don't have to be a statistician to think that is going to be statistically significant.
It is beginning to suggest that there may well be some light at the end of the tunnel. Was the Moderna drug funded by Operation Warp Speed do we know ?
Pfizer one was based on 94 cases so same level of sample, though larger total trial (43,000)
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agent69
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Post by agent69 on Nov 16, 2020 13:09:14 GMT
We were being told that there might be many vaccines for covid that weren't any good or had too many or too severe side effects. Whereas we're seeing most(?) of the covid vaccine being incredibly effective. Anyone, why is this?
Name
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| efficacy
| Sputnik V vaccine
| Russia | 92%
| Moderna RNA vaccine | US | 94.5%
| Pfizer and BioNTech SE
| US/German | 90%
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Am I right in thinkng that 95% effective is twice as good as 90% (as in you are half as likely to contract the virus)?
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mrk
Posts: 807
Likes: 753
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Post by mrk on Nov 16, 2020 13:11:22 GMT
We were being told that there might be many vaccines for covid that weren't any good or had too many or too severe side effects. Whereas we're seeing most(?) of the covid vaccine being incredibly effective. Anyone, why is this? In part because it's important to distinguish "effective at what". These trials are measuring how well a vaccine protects against symptoms. They say nothing about how well they stop transmission. Which is relevant for the famous "herd immunity" effect. It might be that vaccinated people can still catch and transmit the virus, just get less severe symptoms. Also, how effective is the vaccine in older people, that are more vulnerable to Covid-19? Flu vaccines for example are know to be less effective in the elderly. These trial results don't break down by age group. (Although Moderna actually released some data a while ago suggesting their vaccine is effective in older people, more than the other candidate vaccines.) But overall these results are indeed better than expected, and that's why people are excited.
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Post by dan1 on Nov 16, 2020 13:13:50 GMT
If vaccines for sars-cov-2 are so easy* are we looking at a future in which they combine vaccines for the common cold coronaviruses with sars-cov-2? *I jest of course, drunk on the good news this morning
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Post by bracknellboy on Nov 16, 2020 13:25:14 GMT
We were being told that there might be many vaccines for covid that weren't any good or had too many or too severe side effects. Whereas we're seeing most(?) of the covid vaccine being incredibly effective. Anyone, why is this?
Name
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| efficacy
| Sputnik V vaccine
| Russia | 92%
| Moderna RNA vaccine | US | 94.5%
| Pfizer and BioNTech SE
| US/German | 90%
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Am I right in thinkng that 95% effective is twice as good as 90% (as in you are half as likely to contract the virus)? Depends how you are measuring/mean by "twice as good".
To the second part, yes with a 95% vaccine you have 50% chance of catching failing to fight off the virus c.f. a 90% effective vaccine. [sloppy use of language prior to edit)
On the other hand, a 90% effective vaccine is preventing 18/20 instances, and the 95% one is stopping 19/20 instances. Therefore the vaccine is (19/18-1) i.e. 5.55*% better, but the efficacy of both is sufficiently high that translates into a risk reduction of 50% in comparison.
*5.55555555555555555555555555555% using the AC calculator
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