A woman walks past a poster at the Options for the Control of Influenza conference in Hong Kong Sunday, Sept. 5, 2010 in Hong Kong. Robert Webster, chairman of the Department of Virology and Molecular Biology at St. Jude Children's Research Hospital in Memphis, Tenn., urged health authorities around the world to stay vigilant even though the recent swine flu pandemic was less deadlier than expected, warning that bird flu could spark the next global outbreak.