Acambis stands firmly in the "ounce of prevention" camp. The UK biopharmaceutical company specializes in vaccines that protect against infectious diseases. The US government contracted Acambis to build its stockpile of smallpox vaccine (ACAM2000) as concerns about bio-terrorism proliferated following September 11. Under those contracts, the company produced ACAM2000 while it was still an investigational drug; however, the FDA gave it the regulatory nod in 2007. Acambis produces the vaccine for other governments as well, and it is developing non-biodefense vaccines for diseases such as encephalitis, flu, and West Nile virus. The company was acquired by Sanofi Pasteur in 2008.