Researchers with Sinovac Biotech Company begin preparation work to manufacture A/H1N1 influenza vaccine for human use Monday evening, after China receives flu virus "NYMCX-179A" from the World Health Organization, a key ingredient for a A/H1N1 vaccine, on Monday, on June 8, 2009. [Photo: Xinhua] 

A researcher with Sinovac Biotech Company begins preparation work to manufacture A/H1N1 influenza vaccine for human use Monday evening, after China receives flu virus "NYMCX-179A" from the World Health Organization, a key ingredient for a A/H1N1 vaccine, on Monday, on June 8, 2009. [Photo: Xinhua]