1/ Quick update on those risk/reward numbers from JCVI's statement on children 12-15 that have caused so much Twitter controversy. I've got an answer... of sorts...
https://twitter.com/dgurdasani1/status/1434175285113630724?s=20
2/ The controversy revolves round these two tables from the JCVI statement. Table 4 shows estimated number of myocarditis cases resulting from vax. These are in line with US estimates and not controversial. 
3/ It's table 3 that's the problem - the number of nasty outcomes caused by Covid and prevented by vaccination.
Members of iSage say JCVI has got its these wrong by a factor of 6. A simple but fundamental "error" has been made - allegedly
Members of iSage say JCVI has got its these wrong by a factor of 6. A simple but fundamental "error" has been made - allegedly
https://twitter.com/chrischirp/status/1434240235278376960?s=20
4/ The error, they say, is that JCVI uses a fixed population denominator, rather than cases, as used in this alternative analysis by @dgurdasani1 et al osf.io/grzma/
The result, they say, is JCVI under plays the impact of Covid on kids and the benefit of vaccination
The result, they say, is JCVI under plays the impact of Covid on kids and the benefit of vaccination
5/ But I asked the JCVI and they say this is NOT the case. "The JCVI used infection based denominators from modelling and seroprevalence (not fixed populations) to estimate risk per infection", it says
6/ It's analysis is dynamic, reflecting the ebb and flow of the pandemic. It then hits back and says the case (as opposed to infection) based approach used in the paper above is itself flawed, inflating the benefit of vax to kids. It gives these 3 reasons:
7/
i/ It underestimates the denominator infected, so overestimates the risk per infection
ii/ It doesn't account for children who have already been infected and have less to gain from vaccination
iii/ It doesn’t split out high risk kids, so overestimates benefits to the healthy
i/ It underestimates the denominator infected, so overestimates the risk per infection
ii/ It doesn't account for children who have already been infected and have less to gain from vaccination
iii/ It doesn’t split out high risk kids, so overestimates benefits to the healthy
8/ I asked the JCVI for full written details. They said they could not provide now but a full paper covering its methods and calculations would be published soon.
9/ And the lessons from all this?
🧨Publish your workings in full to stop misinformation circulating
🧨 Don't accuse others of errors or malfeasance until you are SURE about what they've done
As @natashaloder put it to iSage last night:
🧨Publish your workings in full to stop misinformation circulating
🧨 Don't accuse others of errors or malfeasance until you are SURE about what they've done
As @natashaloder put it to iSage last night:
https://twitter.com/natashaloder/status/1434941944740864004?s=20
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