Doing the comment section first and then the article and video links.
For those who remember Del Bigtree (the video with the "X's" and "O's" lined up like a two football teams, this may be possible evidence to prove his theory (based on Dr. Geert Vandon Bossche, a major vaccine researcher) is correct.
In the video the following is explained.
Lets us the original Covid virus is called "X."
The vaccines are designed to teach your immune system to go after "X."
But, in the process weakens your immune system to go after variant "O."
So, after the vaccine, one might have good immune response to "X," but reduced immune response to any other variant.
This article states: "The Israeli government said the Pfizer/BioNTech vaccine was about 95.3% effective against coronavirus infections in May. But in June, after the highly contagious Delta variant spread more widely, that number dropped to 64%, the Israeli government said in a brief statement July 5."
If you go from 95% effectiveness against say original virus "X" to 64% effective, that means the vaccine was only 39% effective against variant "O," just like was predicted. When I do the math (95+39)/2 I get 67% so their 64% might be weighted in some way I am not aware of.
I predict they will be promoting a booster shot for Delta, and every new variant as each time you take the shot, you actually weaken your overall immune response ability. This implies an increase in all other diseases as well.