The World Health Organization on Thursday called for "drastic action" to fight the deadliest Ebola outbreak on record, as it announced an 11-nation meeting to address the growing crisis.

As of Sunday, 635 cases of hemorrhagic fever (most confirmed to be Ebola), including 399 deaths, have been reported across Guinea, Liberia and Sierra Leone, making the outbreak the largest ever "in terms of the number of cases and deaths as well as geographical spread," WHO said.

People who watch three or more hours of television daily may be twice as likely to die prematurely than people who watch less, according to a study on Wednesday.

The research in the Journal of the American Heart Association is the latest to describe the potential dangers of a sedentary lifestyle, which include high blood pressure, obesity, cancer and heart disease.

Federal health officials are warning consumers who use popular anti-acne treatments about rare but potentially deadly allergic reactions that can cause swelling of the face and difficulty breathing.

The Food and Drug Administration said Wednesday the problems have been reported with gels, face washes, pads and other products that contain two ingredients: benzoyl peroxide or salicylic acid. But the agency says it's unclear whether those ingredients trigger the reactions or whether some other combination of ingredients is to blame.

Bone marrow transplants save thousands of lives but patients are vulnerable to severe viral infections in the months afterward, until their new immune system kicks in. Now scientists are developing protection for that risky period — injections of cells specially designed to fend off up to five different viruses at once.

"These viruses are a huge problem, and there's a huge need for these products," said Dr. Ann Leen, who leads a team at Baylor College of Medicine and Texas Children's Hospital that found an easier way to produce these long-desired designer T cells.

When it comes to flu vaccines, a federal panel says a squirt in the nose is better than a shot in the arm for young children.

The advisory panel voted Wednesday to advise doctors that FluMist nasal spray is a bit better at preventing flu in healthy young kids. The recommendation is specific to ages 2 through 8 only.

The European Court of Human Rights has told France not to remove life support from a man in a vegetative state for the past six years, blocking a landmark French court ruling.

France's highest administrative court earlier Tuesday gave the green light to end the life of Vincent Lambert, who has been a quadriplegic with severe brain damage since a road accident in 2008, in a decision that went against his parents' wishes.

A group has taken steps to become the first officially recognized marijuana-growing club in Uruguay, where lawmakers have made their country the world's first national marketplace for legal pot.

The Association of Cannabis Studies of Uruguay began the process by registering with the Education and Culture Ministry, Drug Control Chief Julio Calzada said Tuesday.

3-D mammograms may be better at finding cancer than regular scans, a large study suggests, although whether that means saving more lives isn't known.

The study involved almost half a million breast scans, with more than one-third of them using relatively new 3-D imaging along with conventional scans. The rest used regular mammograms alone.

Responding to a major case of research misconduct, federal prosecutors have taken the rare step of filing charges against a scientist after he admitted falsifying data that led to millions in grants and hopes of a breakthrough in AIDS vaccine research.

Investigators say former Iowa State University laboratory manager Dong-Pyou Han has confessed to spiking samples of rabbit blood with human antibodies to make an experimental HIV vaccine appear to have great promise. After years of work and millions in National Institutes of Health grants, another laboratory uncovered irregularities that suggested the results — once hailed as groundbreaking — were bogus.

A leading U.S. doctors' group Tuesday urged parents to read to their children starting in infancy, in order to boost language skills in an age of screens and smartphones.

Pediatricians have long encouraged reading to children, but the guidelines are the first official policy from the American Academy of Pediatrics telling doctors to talk to parents about daily reading to their children, from the first year of life until kindergarten.