Board Change

    Board change

Cambridge, UK and Cambridge, Massachusetts - 16 September 2003 - The Board of
Acambis plc ("Acambis" or "the Company") (LSE: ACM, NASDAQ: ACAM), a leading
developer and manufacturer of vaccines, announces today that Dr John Brown,
Chief Executive Officer, is to step down from his role. Dr Brown has informed
the Board that, after a tenure of nearly seven years as CEO, he believes it is
an appropriate time for a new Chief Executive to continue the Company's
growth.  Dr Brown is continuing to lead the Company while his successor is
sought, the process for which has been initiated.

Commenting on the announcement, Dr Brown said:

"We have had extraordinary success at Acambis and, after nearly nine years with
the Company, most of that time as Chief Executive Officer, it is time to pass
the reins over to a new pair of hands.  I am confident that I leave Acambis in
the best shape it has ever been and, having thoroughly enjoyed my time with
Acambis, I wish the Company and all of its employees every success in the
future."

Alan Smith, Chairman of Acambis, added:

"The Board wishes to place on record its immense gratitude to John for the
significant contribution he has made to Acambis' success.  Under John's
leadership, the Company has grown from an early-stage research company into one
of the leading biotechnology companies in Europe and one of the few that are
profitable. John commands the utmost respect from the Board, his management
team, our employees and peers in the industry. Understanding that he has spent
a great deal of time travelling on company business in the past few years, the
Board recognises his desire to base himself with his family in Scotland.  We
all wish him the best of success with his future plans."

                                    -ends-                                     

Enquiries:

Acambis plc                                                                
                                                                           
John Brown, Chief Executive Officer        Today: [phone]     
                                                                           
Lyndsay Wright, Director of Communications Thereafter: [phone]
                                                                           
Gordon Cameron, Chief Financial Officer    Today: [phone]     
                                                                           
                                           Thereafter: [phone]   
                                                                           
Financial Dynamics                                                         
                                                                           
David Yates/Jonathan Birt                  Tel: [phone]       
                                                                           

Notes to editors:

Acambis is a leading developer of vaccines to prevent and treat infectious
diseases.  Recognised internationally as the leading producer of smallpox
vaccines, Acambis provides governments around the world with the full portfolio
of related smallpox vaccine products required to protect their citizens against
the threat of smallpox virus being used as a bioterrorist weapon. Acambis is
establishing a travel vaccines franchise, including vaccines against yellow
fever, Japanese encephalitis, dengue fever and typhoid. Acambis also has the
most advanced vaccine in development targeting the West Nile virus, which has
spread to over 40 US States in the last three years. Acambis is based in
Cambridge, UK and Cambridge, Massachusetts, US. Its primary listing is on the
London Stock Exchange (ACM) and its shares are listed in the form of American
Depositary Receipts on Nasdaq (ACAM). More information is available at 
www.acambis.com.

"Safe Harbor" statement under the Private Securities Litigation Reform Act of
1995:

The statements in this news release that are not historical facts are
forward-looking statements that involve risks and uncertainties, including the
timing and results of clinical trials, product development, manufacturing and
commercialisation risks, the risks of satisfying the regulatory approval
process in a timely manner, the need for and the availability of additional
capital. For a discussion of these and other risks and uncertainties see "Risk
factors" in the Company's Annual Report and Form 20-F for the most recently
ended fiscal year, in addition to those detailed in the Company's filings made
with the Securities and Exchange Commission from time to time. These
forward-looking statements are based on estimates and assumptions made by the
management of Acambis and are believed to be reasonable, though are inherently
uncertain and difficult to predict. Actual results or experience could differ
materially from the forward-looking statements.



END