Mendel
Senior Member.
They did, an you quoted it. You correctly identified that model 3 compares the previously infected with the infected and vaccinated, same as the Kentucky study. The Israel odds ratio is 0.53 for reinfection, which is the same as 1.89-fold protection; that's well within the expected 1.5- to 3 from the Kentucky study that I talked about in my previous post. (The Kentucky study is more accurate because it had more reinfected people.)Even in this study they wouldn’t tell you how much more it protects you.
While reading the study I found their data came from model three.
Then I did the math.
14,029 people were matched for this study . About 7000 in each group. Out of the people with just natural immunity 37 were reinfected which is .52% of the group. Out of the 7000 people with natural immunity and a vaccination 20 were infected or .286% Which is a overall benefit of less than .25% .
Not not much of a boost in my opinion.
The study is only looking at reinfections that occurred in Israel between June 1st and August 15th 2021. According to Wikipedia, Israel had 101574 cases during that period, which is 1.15% of the population. As more cases pile up, the risk gets bigger, so your 0.52% and 0.25% numbers will also get bigger. What is going to stay the same is that the "infected and vaxxed" group has half as many infected people as the "infected" group. So the "boost" accumulates as case numbers rise. (And the serious side effects of the vaccine are far less than that boost!)
Another part of the same study suggests that the immunity people acquire from an infection gets worse with time, so eventually it's going to make sense to have the booster shot to bring it back up. The Israel study had only half a year elapsed between the infection/vaccination and the outcome survey, so the infection risk is going to be bigger when more time has elapsed (which again results in a better boost).