I sort wish I had AZ instead of fizer as the efficacy seems to last longer & better.
Add some perspective
PZ better in early stages than AZ but longer term AZ slightly better:
Complicated
Study, (requiring a sound understanding statistical concepts). Go down to bottom to graph sections
Hint : odds and probability are not the same thing. Odds = ratio probability of something happening over probability of something not happening
So the study is looking at relative risk.
However you need to transfer that to actual risk.
Eg doing A makes the odds of catching X twice as much as doing B. However what if the actual risk of catching X by doing B is only 1:100000?. That means doing A makes the actual risk of catching X at double which is 1:50000.
At that actual rate, is it important ??enough?.
Don’t forget that in Austrlaia, only 0.6% of the population has been tested positive to Covid.
What is the actual risk of catching Covid when the population hits 80%?. A deep dive into the study will give some info about that.
Study does not extend to 6 months. And it may not be transferable to the Australian setting
What is interesting is the study suggests that a previous natural infection is a powerful immunological primer - much better than a 2Jab ever achieved. Unfortunately it did not have a study arm looking at the odds of catching Covid after a Covid infection compared with catching Covid after a 2Jab vax
My reading is that the risk of becoming Covid positive goes up by about 10% after 3 months with PZ going up a slightly faster
Older age groups are more at risk at any time after 2jab with any Vax than younger age groups. AZ for 35-64 age group about 25% more likely to be positive after 3 months then AZ 18-35 age group. But that does not suggest that a booster for older age reduces that risk difference - the study did not look at booster.
Again , translate to actual risk. If you go out tomorrow what is the chance you will pick up Covid.?. Add 10%. Is that significant? And then factor in a rising community Vax and Reff < 1
In Nsw 374 today became positive out of 8.2 mil. That’s about 0.005%. Add 10% that becomes 0.0055%. About 5.5 in 100000 chance compared with 5 in 100000 chance.
Going to get 3Jab may well be easier than ruminating over this paper. But I hope it puts the risk of waning Vax efficacy in some perspective.