I had a random headache today so I took two Aleve. An hour later I got a call because I'm on a standby list in case someone cancels their vaccination appointment. They said if I came in right away I could take their appointment. So I did, and got the second shot. I haven't had any pain whatsoever, three hours later. I know some of the side effects take awhile, but my wife had extreme arm pain almost IMMEDIATELY. My question is, did I just downgrade the vaccine's effectiveness because I unknowingly took pain relievers before my shot?