The World Health Organization (W.H.O.) is taking urgent steps to develop a new human vaccine for the avian influenza virus in Asia that has mutated from the strain seen in Hong Kong a year ago.
Five human cases have been confirmed by the agency – all in Vietnam, all fatal and all a result of contact with infected chickens. Officials are worried that the new strain might combine with another virus and create a new virus that could spread from person to person.
Genetic and immunologic tests show last year’s vaccine would not protect against this year’s virus.