When the federal government kicked off Operation Warp Speed, the program to administer vaccines, it allowed states to build their own plans. These plans created priority groups, and then sorted those into phases. For example, Oklahoma’s frontline health care workers who treat COVID-19 patients became the first priority group, and composed Phase one. Phase two includes several groups, such as Oklahomans over the age of 65 and health workers not treating COVID-19.
Some states created hard lines between phases. Not Oklahoma.