The CDC is officially recommending a third dose of the Pfizer or Moderna vaccine for people with weakened immune systems. It follows the FDA authorization a day earlier.

Some people have reported getting a lighter or heavier period after getting a COVID-19 vaccine. Cause for concern? Doctors say no. Could it be a temporary side effect? That's harder to determine.

U.S. Olympic heptathlete Annie Kunz says tracking her monthly cycles and learning she needs to eat more and get more naps when she's fatigued has already improved her athletic performance.

Millions of people who need insurance are eligible for free health care plans. A special enrollment period is ending on Aug. 15. Here's how to sign up in time.

The state has one of the lowest vaccination rates in the U.S. And this weekend, 80,000 doses will expire because of lack of demand. The campaign is on to get people to sign up.

Weeks after the Food and Drug Administration approved the Alzheimer's drug Aduhelm, doctors are struggling to figure out who should get the drug and how to use it safely.

A small Israeli study of vaccinated health care workers found that a handful who got infected developed headaches, muscle pain, fatigue and other symptoms of long COVID that lasted for weeks.

It protects from drizzles and thunderstorms but not a hurricane. In other words, if you are exposed again and again to infected people, there's some risk you could get sick.

Nope, they won't put a microchip in you. And the side effects usually aren't that bad. And if you want to get your HPV shot at the same time, that totally works. Read on for these and more answers.

New estimates show the U.S. is on track to see a big rise in cases and more than triple the number of deaths by October.