With potential authorization for a COVID-19 vaccine by the Food and Drug Administration within striking distance, scientists and public health experts are deliberating which Americans should receive the initial, limited supply. A panel of experts gathered this week has recommended prioritizing front-line health care workers, followed by adults with serious underlying medical conditions and seniors living in nursing homes or crowded living environments.

The recommendations, made by a committee of scientists from the National Academies of Science, Engineering and Medicine, were part of a first draft of recommendations for COVID-19 vaccine prioritization. Once finalized, those recommendations will be handed over to the Centers for Disease Control and Prevention, tasked with rolling out the vaccine.

The committee included representation from experts in epidemiology, vaccine research, public health, ethics and law.

“We looked at issues of ensuring maximal benefit, promoting common good, saving the greatest number of lives possible,” Dr. Helene Gayle, committee co-chair, said during her opening remarks for the Equitable Allocation of COVID-19 Vaccine Public Listening Session, which took place virtually on Sept. 2.

The plan, as introduced by the document, details a four-phase approach, with Phase 1 serving workers in health care facilities and at-risk seniors. Phase 2 includes other medically high-risk individuals and other essential workers, such as teachers and school staff. Phases 3 and 4 will ultimately reach healthy adults and children who are yet to be vaccinated.

During a public hearing, some doctors and public health experts expressed concerns over the committee’s decision to not explicitly prioritize race and ethnicity. The pandemic has disproportionately impacted Black and Hispanic people and other people of color.

“Any strategy to decrease the mortality rates due to coronavirus must account for the greater percentage of Black and brown deaths per capita,” said Dr. Randall Morgan, executive director of the Cobb/National Medical Association Health Institute, which promotes the interests of over 50,000 African American physicians. “The causes are multifactorial, however, the lack of availability or acceptance of the vaccine will simply compound this situation.”

The committee, however, offered reassurances that although race is not a criteria for vaccination, the plan does take race into account. Early vaccine efforts will target communities hit hardest by COVID-19 based on the CDC’s “Vulnerability Index,” a calculated measure of who is most vulnerable.

“We took the approach that this virus doesn’t understand skin color at all, but it understands vulnerabilities: heart failure, kidney failure, a body mass index greater than 40,” said Dr. William Foege, co-chair of the committee. “Some of the social vulnerabilities have to do with crowding, with people who have to go to work and don’t have an option, with multigenerational occupancy. So we looked at those things and we put those first in line rather than saying skin color is the way we’ll make this decision.”

The plan set forth by the committee will continue to be adapted over the coming weeks and months, and a version of it may ultimately serve as the primary framework for guiding vaccine distribution in the United States.

But this isn’t the only committee weighing in on the highly debated topic of who should get a vaccine first. While most experts agree that vulnerable populations should receive vaccine priority, not everyone agrees which members of society are the most vulnerable.

An editorial released Thursday in the journal Science focused on another metric: years of life saved. This group, a consortium of global experts, criticized population-based vaccine allocation.

Instead, they used a metric called “standard expected years of life lost” — effectively a way to measure the collective benefit of vaccines in terms of preventing premature death. With this model, premature deaths are most common in countries with fewer resources, less capable of hospitalizing and treating patients who would otherwise survive.

“Equally populous countries can face markedly different levels of premature death and economic devastation from COVID-19,” the authors wrote, arguing that their model would create a more equitable vaccination strategy for lower-income countries.

Meanwhile, the World Health Organization suggests that countries should receive vaccine doses proportional to population, regardless of that country’s income.

Similar to the National Academies of Science, Engineering and Medicine’s approach, it would start with health care workers, older adults and high-risk individuals, with the ultimate goal of providing vaccination to 20% of the population of participating countries by the end of 2021.

Dave Harrison, M.D., is a pediatric cardiology fellow in Boston and a contributor to the ABC News Medical Unit.