Shares of Acambis plc plunged 40 percent on news that the U.S. Department of Health and Human Services (HHS) rejected the company's proposal to provide 20 million doses of its modified vaccinia ankara (MVA) smallpox vaccine. (BioWorld Today)

Shares of Acambis plc plunged 40 percent on news that the U.S. Department of Health and Human Services (HHS) rejected the company's proposal to provide 20 million doses of its modified vaccinia ankara (MVA) smallpox vaccine. (BioWorld Today)