Too many variables.
Some jabs are F'd up in manufacturing (as in Baltimore).
Some jabs are sabotaged along the way.
Some jabs are injected intradermally not intramuscularly.
Some people have different absorption of the mRNA in their cells and different activation.
People have different amounts of spike expression in their cell membranes and different amounts breaking loose and getting into the blood.
Some people have different immune responses to the jab, such that any free spike in their blood is taken out quickly, some don't.
And so on, and so on.
Yes, I believe there's a lot of variation and not much predictability. Some friends and relatives, invluding 90 years old, had no reaction at all. Others who were younger had bad reactions (fever, chills) and won't go back for a "booster".
What do you think of the dicussion of the results at the bottom of this study: https://www.degruyter.com/document/doi/10.1515/cclm-2021-0339/html of why they believe that the spike protein was undetectable in the blood of pfizer recipients. The test had a range down to 2 pg/ml.
I pinged ransomnote so he can determine, using his expertise, whether this study or those measurements were faked by a Gates-controlled organization.