Priority groups Early variation in COVID-19 vaccination rates had much to do with a countyâs proportion of health care workers, the first group able to get vaccine. With people 65 and older becoming eligible in late January, a countyâs share of seniors has also played a large role in its overall rate, experts say. But with everyone 16 and older approved for vaccination early this month, such factors are beginning to wane. However, a countyâs racial makeup can also influence its immunization rate, given that rates statewide are significantly lower for Blacks and Hispanics, and somewhat lower for American Indians and Asians, than for whites.