Sinovac Biotech Ltd. is a holding company, which engages in the research, development, manufacture, and commercialization of vaccines that protect against human infectious diseases. Its product portfolio includes vaccines against enterovirus71, or EV71, hepatitis A and B, seasonal influenza, H5N1 pandemic influenza, H1N1 influenza, and mumps. The company was founded in 1993 and is headquartered in Beijing, China.