I had the same issue. My platelet count started at 400 and started rising after I had the covid shot. I also tested positive for RA after I had the vaccine. After seeing an RASpecialist and more tests which came back negative for RA, my platelets started rising, and have continued to do so. I tested positive for Et jak2 mutation. My last count was 601. I am only taking a low dose aspirin for now.
I am 78, and feeling good which is why I don’t want to go on any medication. I only had the first two shots, and will never have another one.