sinovac biotech ltd. is a china-based biopharmaceutical company that focuses on research, development, manufacturing and commercialization of vaccines that protect against human infectious diseases including hepatitis a and b, seasonal influenza, h5n1 pandemic influenza (avian flu), h1n1 influenza (swine flu), and mumps, as well as animal rabies vaccine for canines. in 2009, sinovac was the first company worldwide to receive approval for its h1n1 influenza vaccine, panflu.1, and has manufactured it for the chinese central government, pursuant to the government-stockpiling program. the company is also the only supplier of the h5n1 pandemic influenza vaccine to the government-stockpiling program. sinovac is developing a number of new pipeline vaccines including vaccines for enterovirus 71 (against hand, foot, and mouth disease), of which the ev71 vaccine is currently in phase iii clinical trials, pneumococcal conjugate, pneumococcal polysaccharides, and rubella. sinovac sells its vaccine