Health officials are releasing the first nationally representative estimate of how many U.S. adults have chronic fatigue syndrome: 3.3 million.

“I could never get a full breath. I felt I was going to die,” said Louise Salant.

Research in U.S. veterans provides fresh evidence that long COVID-19 can happen even after breakthrough infections following vaccination.

President Joe Biden is ordering a new national research push on long COVID, while also directing federal agencies to support patients dealing with the mysterious and debilitating condition.

Experts say it's too early to know whether people infected with the omicron variant will develop long COVID.

Omicron's race across the globe has amped up concerns about long COVID, which some estimates suggest affects a third of COVID-19 survivors.

Arizona Gov. Doug Ducey says President Joe Biden is overreaching with his new requirement for employees of large businesses to be vaccinated or regularly tested for COVID-19.

A well-known Jacksonville infectious disease expert is sharing his frustration after learning a nurse is being investigated for allegedly writing mask opt-out notes at a public park.