The race for a coronavirus vaccine is showing positive results, but medical experts say when it becomes available drug makers won't be able to produce enough doses for the entire country, creating difficult questions about who gets it first.
Large-scale trials of vaccines developed by companies including Pfizer and Cambridge-based Moderna are underway, involving tens of thousands of people, with scientists tracking the rates of infection among people who get the vaccines versus those who don't. Results are expected in the next several months.
Meanwhile, the National Academies of Sciences is developing a vaccine distribution plan under direction of the federal government, which is expected to be released in October.
Medical experts say an effective vaccine is crucial to ending the pandemic, which has sickened nearly 5.5 million and killed more than 170,000 nationwide. But getting to that point will mean resolving a host of complicated ethical issues about how a vaccine is developed — and who should be first in line to get it.
"The supply will probably not meet the demand initially, which happens with any new vaccine that's developed," Dr. Howard Koh, a professor at Harvard University's T.H. Chan School for Public Health. "There will have to be priority groups, and some difficult decisions will have to be made."
Dr. David A. Rosman, president of the Massachusetts Medical Society, says the general consensus in the medical community is that workers on the front lines of the battle against COVID-19 should be the initial round of vaccinations.
"That doesn’t mean just doctors and nurses but workers who stock shelves and clean the floors," he said. "It means people who work in grocery stores, deliver our food and other front-line workers who keep society running while others are able to work from home."
Rosman said equally important is ensuring that the development of a vaccine accounts for racial and ethnic groups that have been disproportionately impacted by the virus. He said early human trials of vaccines have been made up of predominately of white participants.
"We need to make sure that the trials are done in an ethical way, and that there’s diversity in who is getting it," he said.
Experts said another big question is whether the initial goal of a wide-scale vaccination program is to minimize coronavirus cases or deaths.
Giving the vaccine to those transmitting the disease, such as younger adults, would help create herd immunity more quickly and prevent the spread of coronavirus. Providing it to older adults first will likely save more lives, but the elderly are often have a weaker response to vaccines.
Koh, a former assistant secretary at the U.S. Department of Health and Human Services, said once a vaccine is available there has to be robust public outreach to assuage any public fears about taking a new drug.
"The public messaging will be extremely important," he said. "People need to be assured that it's something that will improve their health and not hurt them."
The global race for a coronavirus vaccine has dramatically shortened a development and trial process that generally takes years, if not decades, experts say.
Dr. Anthony Fauci, the nation's top infectious disease expert, said recently he is confident that a coronavirus vaccine will be ready by early next year.
But even if the most optimistic projections hold true and a COVID-19 vaccine is cleared for use by the Food and Drug Administration late this year, the vast majority of Americans won’t be able to get the shots until spring or summer next year at the earliest, Fauci said.
The federal government has signed deals with at least six vaccine makers to produce coronavirus shots when approved and clear the way for wide-scale production.
The Trump administration's Operation Warp Speed program is pledging to deliver 300 million doses of a safe, effective vaccine by January 2021.
To date, the program has handed out almost $10 billion to companies developing vaccines.
Rosman said the federal government needs to do a much better job with vaccine distribution than it did with distributing personal protective equipment and other supplies to states battling the virus, which he called a "failure."
"We have to get this better when it comes to vaccines," he said. "It’s a matter of life and death, and the key to reopening our society."
Christian M. Wade covers the Massachusetts Statehouse for North of Boston Media Group’s newspapers and websites. Email him at email@example.com.