Who’s eligible for vaccination?

People at highest risk for infection are being prioritized for vaccination, including people living with HIV, men who have sex with men and people who are already eligible for preventive HIV therapy, Walensky said.

That includes about 1.7 million Americans, she said.

About 600,000 doses have been made available, and nearly the same number are due to arrive shortly, administration officials said. Delivering the vaccine to a shallower layer of the skin would allow five people to be vaccinated from the same vial now used for each person. Dr. Robert Califf, head of the Food and Drug Administration, said the new route of administration is just as easy to deliver as well as safe and effective.

The FDA will make a final decision about whether to change the shots within the next few days, he said.