I am not sure how they came to that conclusion, but I do see several Pollyanna statements in this article not backed up by any facts or research. Such statements don't have any more basis in reality than someone claiming, "We're all going to die!"
So far we have been lucky. Unfortunately that too produces a careless attitude that converges toward unintended consequences.
Moderna has said, and I did work in biotech to confirm this, that a new vaccine with a new variant included for immunity would be a cakewalk.
I am not sure what you are questioning..they know delta emerged in India in Nov 2020.
It is dominant because it is so contagious.
Did you read the link?
https://www.pnas.org/content/115/51/12878
They took what was the equivalent of a plastic/fake virus body and stuck the spike protein on it, gave it to animals, and the animals got very sick/died. Conclusion being that the spike protein IS the part of covid we want to attack with a vaccine.
Both Modern a and Pfizer used every single epitome on the spike protein, the whole enchilada, in their mrna recipe.
So ok, maybe people with covid made antibodies to other parts of the virus, maybe an epitome on its bottom or something. But is it relevant, or iow is it pathogenic?
The whole premise is that antibodies to only the spike protein make covid vaccines leaky.
So for instance with Hep B, they took the main antigen, the one we use for testing in fact, and created a vaccine from it. But then they found people still had the disease, while testing neg for the antigen. So obviously more of the virus than that *one* antigen causes disease. In the case of covid vaccines, however, the spike protein contains many antigens, and we vaxxed are indeed making poly clonal abs.
Way back in the 1980s I got the vaccine series. And OMG I was mouthpipetting racks and racks of greenish-sera hep samples for testing. I never got Hep B.