Omicron has many more mutations than previous variants of concern, a fact that raises questions about how effective existing vaccines will be against the new form of the coronavirus.

The companies say a study of more than 10,000 volunteers showed a vaccine efficacy of 95% or greater for people receiving the booster.

A new Alzheimer's drug isn't reaching many patients. Doctors say reasons include its high cost, and lingering questions about its effectiveness.

Officials say the recall was prompted after a random sample tested positive for the organism listeria monocytogenes. No illnesses have been reported, the FDA says.

The Food and Drug Administration also gave an OK to boosters that differ from the vaccine originally used to immunize people against COVID-19. A mix-and-match approach could ease the booster rollout.

A panel of experts voted to recommend that the Food and Drug Administration authorize a booster dose of the Johnson & Johnson COVID vaccine at least two months after the first shot.

The FDA has issued new targets to reduce the amount of salt that manufacturers put in their foods. It could prevent thousands of cases of cardiovascular disease.

Johnson & Johnson has asked the Food and Drug Administration to authorize a booster for people 18 and older six months after initial immunization, with an option to vaccinate after two months.

The Food and Drug Administration released briefing documents Tuesday on booster shots for the Moderna and Johnson & Johnson COVID vaccines ahead of a two-day advisory meeting that starts Thursday.

The company says that daily exposure levels believed to be detected in the products likely would not cause "adverse health consequences."

Dr. Janet Woodcock, an administrative veteran of the Food and Drug Administration since the 1980s, has been acting director of the agency since January. Why is the permanent job so hard to fill?

The leaders of two federal health agencies are telling White House COVID-19 advisers that there is not enough data right now to make a blanket recommendation on boosters.

Moderna submitted data from 344 volunteers who got a third shot of the vaccine six months after their first two doses. The additional shot significantly boosted immunity, the company said.

Using the COVID vaccine "off-label" — whether that's for booster shots or young children — may be tempting to some vaccine providers, but the CDC warns it could get them into trouble.

The FDA announced the Pfizer vaccine is the first in the U.S. that is now fully approved. Here's what that means for vaccine mandates and convincing vaccine-hesitant people to get vaccinated.