There are enough problems with the vaccines without added one based on a misinterpretation.

They now have six months of data, so they can say that the antibodies persist through six months. They do not report outcomes beyond six months, which they would have had to do for your 'only' qualifier to be proven. Now, it might still turn out you are predicting accurately the extent of the protection, but if someone uses your post on a medical friend right now, they will get their head handed to them.

If you want to report vaccine problems, look at blood clots, fatalities, and people getting shots and still getting COVID. Plenty of problems!