Walk-in COVID-19 vaccine clinic to be held at Trinity Assembly of God Walk-in COVID-19 vaccine clinic to be held at Trinity Assembly of God By Tiffany Bechtel | April 5, 2021 at 7:23 PM CDT - Updated April 5 at 7:23 PM LAWTON, Okla. (TNN) - The Oklahoma State Health Department will be hosting a walk-in COVID-19 vaccine clinic at Trinity Assembly of God Tuesday, April 6. The clinic will be held at Trinity Assembly of Godâs location at 202 SE 45 St. in Lawton from 9 a.m. to 11 a.m. The clinic is open to anyone aged 16 years or older, but minors must be accompanied by a parent or guardian.