It is available, at least in NYC.
New York State is currently largely in line with CDC, and offer Pfizer & Moderna boosters to specific groups in line with CDC recommendations (over 65, 18+ with underlying conditions, high risk jobs, nursing homes). NYS currently recommends sticking with the same shot you got before, but offer a choice of any. NYC Latest recommendations:
COVID-19: Vaccine - NYC Health
Coronavirus Disease 2019
CDC provides credible COVID-19 health information to the U.S.