The israeli data has issues because it was during the initial surge of delta which was predominantly in cities with high vaccination rates, which drives the VE down if you compare it against the population-wide ratio of vaccinated to unvaccinated.
Most studies of VE also do statistical modelling of how many of the unvaccinated have been infected and are actually recovered. This was the case of the CDC study from yesterday which had the headline number of only 66% efficacy against delta, but if you dig into the data they didn't test for antibodies or anything but modeled viral spread and had a 95% CI on that number of 26% to 84%.
That is literally garbage data.
The actual value could be closer to the higher end due to them underestimating community spread (pretty plausible) and due to selection effects where their unvaccinated population was higher risk for prior infection than they thought.
I thought that study might change my mind on the situation since they had done a much better job than the Israeli data on controlling for age, comorbidities, etc. But when you get down to it the VE data was still crap. And the mention of waning immunity seemed to be just tacked on with no supporting evidence other than the lower number VE number against delta.
Similarly, its now been found that the studies which equated similar Ct values to viral load are bad because there's less culturable virus in vaccinated individuals, and the Ct values drop faster which indicates vaccinated individuals are producing more viral debris at peak Ct and clearing the virus faster. So they would therefore be expected to have less transmission. Since they're staying out of the hospital and Ct values correlate somewhat with symptom severity that also suggests less transmission (the people who wind up hospitalized most likely transmit more before they get there).
Then there's that silly study out of China which found the odd result that viral-load-as-measured-by-Ct where 1,000 times higher against delta than against original Wuhan strain data from the pandemic when measured at the onset of symptomology (so not peak data, not average data, and compared against the earliest PCR results against the original pre-D614G virus). That quietly disappeared from scientific discussions, but the media keeps on citing it as the truth without any qualifications.
We know that vaccination reduced actual transmission and attack rates against Alpha and its very likely that it does the same against Delta. No data has contradicted that yet.
And I can't explain why so many scientists are so eager to undermine the message of vaccine efficacy. I guess they think it'll be easier to get vaccinated people to mask up than it is to get the unvaccinated to get vaccinated, and some of them are presumably just as addicted to bad news on facebook and twitter as the rest of the population is.
Ok thanks, that is informative. From a policy perspective I think it is a bad idea to basically promise everything can return to normal after vaccination, if this appears to not have worked out in places like Israel. In Germany they are phasing out free antigen tests and they are not required for vaccinated. Both seem like really short-sighted policies.
Most studies of VE also do statistical modelling of how many of the unvaccinated have been infected and are actually recovered. This was the case of the CDC study from yesterday which had the headline number of only 66% efficacy against delta, but if you dig into the data they didn't test for antibodies or anything but modeled viral spread and had a 95% CI on that number of 26% to 84%.
That is literally garbage data.
The actual value could be closer to the higher end due to them underestimating community spread (pretty plausible) and due to selection effects where their unvaccinated population was higher risk for prior infection than they thought.
I thought that study might change my mind on the situation since they had done a much better job than the Israeli data on controlling for age, comorbidities, etc. But when you get down to it the VE data was still crap. And the mention of waning immunity seemed to be just tacked on with no supporting evidence other than the lower number VE number against delta.
Similarly, its now been found that the studies which equated similar Ct values to viral load are bad because there's less culturable virus in vaccinated individuals, and the Ct values drop faster which indicates vaccinated individuals are producing more viral debris at peak Ct and clearing the virus faster. So they would therefore be expected to have less transmission. Since they're staying out of the hospital and Ct values correlate somewhat with symptom severity that also suggests less transmission (the people who wind up hospitalized most likely transmit more before they get there).
Then there's that silly study out of China which found the odd result that viral-load-as-measured-by-Ct where 1,000 times higher against delta than against original Wuhan strain data from the pandemic when measured at the onset of symptomology (so not peak data, not average data, and compared against the earliest PCR results against the original pre-D614G virus). That quietly disappeared from scientific discussions, but the media keeps on citing it as the truth without any qualifications.
We know that vaccination reduced actual transmission and attack rates against Alpha and its very likely that it does the same against Delta. No data has contradicted that yet.
And I can't explain why so many scientists are so eager to undermine the message of vaccine efficacy. I guess they think it'll be easier to get vaccinated people to mask up than it is to get the unvaccinated to get vaccinated, and some of them are presumably just as addicted to bad news on facebook and twitter as the rest of the population is.