Ihad no problem getting an appointment/. I'm in Cheektowaga and went to Niagara Falls. Made it on March 29th and went on April 5. Could have went April 2, but my schedule couldn't fit it in. Mother had one (J&J) at the house (she is housebound). By the 31st we will all be done.
The possible third shot is because of the mutation rate of the virus, not how effective it is. Its an arms race between your immune system and the virus. If the coat protein spikes mutate, the antibodies you make to the coat protein are not effective. Think lock and key. Change the lock and the key doesn't work.