Israel: Pfizer vaccine prevents 98.9 percent of Covid-19 deaths(thehill.com)
thehill.com
Israel: Pfizer vaccine prevents 98.9 percent of Covid-19 deaths
https://thehill.com/policy/healthcare/public-global-health/539778-israel-pfizer-vaccine-prevents-989-percent-of-covid-19
11 comments
Is there any information on how well Pfizer / Moderna do against the South African strain?
As far as I’ve read, no data on clinical effectiveness of the mRNA vaccines against the SA strain. There have been several reports where groups measure neutralizing antibodies in serum of people who have received vaccines against the various variants (with some methodological differences between those reports). One recent preprint found a 100 fold drop off in neutralizing activity against the SA strain (https://www.medrxiv.org/content/10.1101/2021.02.14.21251704v...), but others have found a less steep drop off. Also, that’s just measuring neutralizing antibodies, not other cell-mediated components of the immune response, and it is not clear what dropoff in neutralizing antibodies is clinically meaningful. I think there is data on the reduction in hospitalizations and deaths with other vaccines against the SA strain, but I don’t have those refs on hand. I imagine clinical data on the mRNA vaccines and the SA and P1 strains is being gathered now.
This preprint seems to indicate Pfizer vaccine is effective against the SA strain:
https://www.biorxiv.org/content/10.1101/2021.01.07.425740v1
https://www.biorxiv.org/content/10.1101/2021.01.07.425740v1
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without context it is hard to make sense of this number. Does this mean 1.1% of COVID cases still result in death? Wasn't 1% about the guesstimated death rate already? What about in older age groups?
It means that if you have two similar and equally large groups of people, except that one is unvaccinated and the other has received the pfizer/biontech vaccine, and 1000 people in the unvaccinated group dies from covid, then you may expect 11 people in the vaccinated group to die. That is, the vaccine prevents 989 of the 1000 deaths that you'd see if the vaccinated group were unvaccinated, leaving 11.
I mean, that is the assumption right? I' m just complaining about how it was written in the article(s)
For a critique of a lesser number from yet another leaked preprint with the same status that only concluded 89.4%, see https://twitter.com/ZoeMcLaren/status/1363582050775744515
The bottom line is: results are positive, but every single one reported in headlines is likely overstating.
70% RRR (relative risk reduction) efficacy is supported by data, if I understand it. >80% or <50% is not - at least not with publicly available data.