By April 17, 2002, only 15 million doses of aging smallpox vaccine were found. However, when tested in human volunteers at a dilution of one to five, that vaccine successfully immunized 99 percent of tested subjects, thus increasing the supply of smallpox vaccine from 15 million to 57 million doses. Further, even when the vaccine was diluted tenfold, the results proved efficient in 97 percent of those inoculated and now yielded 150 million doses of vaccine. The pharmaceutical firm Aventis Pasteur found and donated an additional 85 million doses. Finally, the government ordered from a private company, Acambis, an additional 155 million vaccine doses. Hence, the drive was accelerated to obtain, store, and use smallpox vaccine.

UPDATE 3-Sanofi to buy vaccine maker Acambis for $548 mln - Reuters Jul 25, 2008 - Sanofi-Aventis SA (SASY.PA)agreed on Friday to buy British vaccine maker Acambis PlcACM.L for 276 million pounds ($547.8 million), in a dealhighlighting big drug companies' hunger for biotech assets.