Acambis PLC Delivers ACAM2000(TM) Doses to US Government; Increases 2007 Revenue Expectations

Cambridge, UK and Cambridge, Massachusetts – 31 December 2007 – Acambis plc (Acambis) (LSE: ACM), a leading vaccine development company, announces that, subsequent to the US Centers for Disease Control and Prevention (CDC) order of September 2007, it completed delivery of the entire 2.7 million doses of its ACAM2000™ smallpox vaccine to the CDC on 28 December 2007. This was ahead of the scheduled delivery in the first quarter of 2008.