The Pfizer and Moderna Covid-19 vaccines could be approved in a matter of weeks, but who in the United States will get them first?
A high level panel of US experts on Tuesday voted that health care workers and residents of long-term care facilities should be prioritised in the first phase.
"I believe that my vote reflects maximum benefits, minimum harm, promoting justice and mitigating the health inequalities that exist, with regard to distribution of this vaccine," said Jose Romero, chair of the Advisory Committee on Immunization Practices at the Centers for Disease Control and Prevention.
As the sequence continues though, US experts may differ from other countries in prioritizing "critical workers" who keep society running -- potentially even before people at highest risk.
To be clear, there won't be one single set of rules for the whole nation.
At the risk of creating confusion, which was the case during the vaccine campaign against the H1N1 flu in 2009, the federal government only makes recommendations to states, which decide for themselves how to distribute the doses and who gets priority.
Panels of top experts have already delivered their opinions, which diverge in certain key respects and reveal the tension at the center of the debate: vaccines should both protect the most vulnerable and help facilitate a return to normal.
It's on the question of jumpstarting the economy as quickly as possible that the US may set itself apart.
France's top health authority recommended starting with retirement home residents and employees who work there, followed by the elderly and health care workers, then the over-50s, people whose jobs put them at risk, medically high-risk people, the poor, and finally the rest of the population.
That's the approach recommended by the World Health Organization and adopted by a number of rich countries, Saad Omer, director of the Yale Institute for Global Health, told AFP.
In the US, the panel voted overwhelmingly in favor of prioritizing health care workers and long-term care facilities, which have accounted for about 40 percent of deaths in the country so far.
The committee did not vote for what would happen after the initial phase, but experts have proposed to then give priority to essential workers in phase "1b," followed by adults with multiple risk factors and adults over 65 in phase "1c."
Essential workers include teachers, workers from slaughterhouses to the supermarkets who keep Americans fed, and those who drive buses and trains, sell them their medicine, maintain order, or deliver mail and parcels.
People in these jobs are often minority Hispanics or Black, and have been hit disproportionately by the pandemic.
In practice, these ethical, epidemiological and economic considerations may be ignored in the initial rush on doses.
Problems remain to be solved: though it may be easy to target retirement homes and hospitals, how are pharmacists and doctors supposed to confirm that a person is indeed an essential worker, or that they have two underlying conditions?
The Trump administration has said that retirement homes will receive Pfizer/BioNTech vaccines as early as mid-December in the event of a regulatory green light.