Moderna reveals the limits of making a coronavirus vaccine

Moderna said Thursday that starting in 2021, it could manufacture "possibly up to 1 billion doses per year" of its experimental coronavirus vaccine with the help of a contract manufacturer.

Yes, but: 1 billion vaccine doses may sound like a lot, but government and public health leaders would inevitably still have to make hard choices about who should get the vaccine first.

By the numbers: 500 million people could get vaccinated from 1 billion vaccine doses, based on Moderna's tests of one person getting two 100-microgram shots.

• There are 7.8 billion people on Earth, meaning Moderna's vaccine could initially cover 6% of the global population.

This scenario assumes the vaccine clears all clinical hurdles and is deemed safe and effective — which are major unknowns right now — and that it eventually gets FDA and other international governmental approvals.

• This scenario also assumes 1 billion doses can actually be made within a year, which many experts believe is difficult to do.

The burning questions: That production level not only falls short of immediate need, but all 1 billion doses also will not come out at the same time. It's leading ethicists to consider the following:

• Which clinics, hospitals and other facilities will get it?
• Will health care workers, older people in places like nursing homes and others with compromised immune systems be prioritized? If so, who comes after?
• If there are new coronavirus outbreaks, should those locales get an influx of the vaccine?
• What if the vaccine costs a couple hundred dollars, like other vaccines? Will everyone be able to get it regardless of insurance coverage or ability to pay?
• Since Moderna is based in the U.S., will the U.S. prioritize itself over other countries, and will it cut deals with other countries?

Between the lines: It's naive to think the most affluent people won't try to get it immediately.

• "The very rich … will do anything to get it, and there will be a black market," said Arthur Caplan, a bioethicist at New York University, adding he's "200% sure" that would occur given what happened when ventilators were in short supply.

The bottom line: Even with other coronavirus vaccines rapidly moving through clinical trials, billions of people simply won't have access to a vaccine by 2021.

• And if history is any indication, the poor and minorities will be at the back of the line unless equitable national and global policies are put into place.

Go deeper: How the U.S. might distribute a coronavirus vaccine