In a presentation to the committee, Dr. Mary Chamberland, representing the CDC, said ACIP has agreed to follow the principles of maximizing benefits and minimizing harms, promoting justice and mitigating health inequities in determining early allocation groups.

ACIP discussed four overlapping groups who are at high risk of getting COVID-19 that might be prioritized in getting the vaccine. The schedule of which groups get the vaccine when will depend on characteristics of the vaccine and quantities available, the advisers said.

Still, a consensus has formed that health care personnel should be first in line to get the vaccine, given their high risk of exposure. Health care workers are defined by ACIP as “paid and unpaid persons serving in health care settings who have the potential for direct or indirect exposure to patients or infectious materials.” This population is estimated at 21 million.

A second group outlined by ACIP would be much larger — 87 million. This would include workers in other essential areas, defined as persons who “conduct operations vital for continuing critical infrastructure, such as food, agriculture, transportation, education and law enforcement.”