A Nobel prize-winning scientist Tuesday played down “shock-horror scenarios” that a new virus strain will emerge with the potential to kill millions of people.

The only person in Taiwan known to be infected with the H7N9 avian flu continues to make progress and is now free of the virus, doctors said Sunday.

A study in England has strengthened evidence from Scandinavia that a vaccine used to prevent pandemic flu boosted the risk of sleep disorder among teens and children, doctors said on Tuesday.

A U.S. government analysis of this season's flu vaccine suggests it was effective in only 56 percent of people who got the shot, and it largely failed to protect the elderly against an especially deadly strain circulating during flu season.

Coughs usually take longer to clear up than people think, and the gap between how long people expect then to last and how long it actually takes may drive some patients to the doctor for antibiotics that won't help, according to a U.S. study.

Influenza has officially reached epidemic proportions in the United States, with 7.3 percent of deaths last week caused by pneumonia and the flu, the U.S. Centers for Disease Control and Prevention said on Friday.

One of the worst U.S. flu seasons in a decade has created shortages of vaccine and the Tamiflu treatment for children, raising the prospect that people considered at high risk of getting the flu might not get the protection they need.

Two Chinese women have died from the H1N1 flu strain in Beijing in the past 10 days, Chinese state media said on Sunday, the first reported deaths from the virus in China's capital since 2010.

Indonesia has identified the bird flu virus that killed hundreds of thousands of ducks in recent weeks as a more virulent type which is new to the country, according to a letter seen Tuesday.

Animal health officials have imposed a ban on the movement of chickens at a farm in southern Taiwan that has been found infected with low-pathogenic H5N2 avian influenza.