Confirmed cases of H7N9 bird flu drug resistance

Laboratory tests have confirmed resistance in three people infected with the H7N9 strain of bird flu to a common group of antiviral drugs including Tamiflu, said a study published by The Lancet on Tuesday.

The "apparent ease" with which resistance emerged in H7N9 viruses to the only available treatment is a cause for concern, said the Chinese researchers who conducted the study.