U.K. and U.S. teams used computer models to work out the possible scenarios that could occur if the H5N1 avian influenza virus mutated and became capable of spreading from human to human. The result could be deaths on the scale of the 1918 Spanish flu epidemic that claimed between 20 million and 40 million lives. However, a combination of surveillance and the targeted use of antiviral drugs could halt it, the teams told the journals “Nature” and “Science.”
The models used by both teams were nased on incidences and controls used in Thailand, one of the countries at highest risk from bird flu. More than 50 people have died from the virus in southeast Asia since the first human cases were reported in 1997.
Currently, the H5N1 avian influenza poses a limited threat to humans because it is difficult to transmit from person to person. But health experts fear the H5N1 virus could acquire this ability, causing an influenza pandemic that could kill as many as 50,000 people in the United Kingdom alone.
Professor Neil Ferguson of Imperial College in London and his colleagues found two specific conditions that would have to be met to limit an outbreak of human-transmissible avian influenza to fewer than 200 cases. First, the virus would have to be identified while confined to about 30 people. Second, antiviral drugs would have to be distributed rapidly to the 20,000 people nearest the infected individuals.