If it comes down to then being required again I'll look out for those and give them a try.
I'm in the US, I think we have had maybe the best access to these vaccines. I just checked one pharmacy in my area, 17 locations within 30 miles all with appointments today, I can even choose between Moderna and Pfizer. I haven't gotten a booster in a while, but I want to say I've gotten the first two shots and like 2-3 boosters. The last booster was an updated one I think for Delta.