Holding(s) in Company

    Holding in Company

Cambridge, UK and Cambridge, Massachusetts - 19 December 2003 - Acambis plc
("Acambis") (LSE: ACM, NASDAQ: ACAM) notes that Baxter International, Inc.
("Baxter") (NYSE: BAX) yesterday filed a Schedule 13D with the US Securities
and Exchange Commission announcing the sale of all of its equity shareholding
in Acambis.

Baxter's relationship with Acambis dates back to September 2000 when Baxter and
Acambis commenced a strategic collaboration at which time the two companies
entered into commercial agreements and a subscription agreement.

The subscription agreement was for £27.8 million of Acambis ordinary shares at
a weighted average price of 130p over a three-year period, which resulted in
the issue of 21,349,994 shares or 20.3 per cent of Acambis' issued share
capital.

The commercial agreements covered contract manufacturing, technology transfer
and distribution arrangements between the two companies. The collaboration was
subsequently expanded to encompass a lease financing arrangement and
partnerships to bid for and win contracts around the world to supply smallpox
vaccines. Most notably, Acambis and Baxter teamed up to win a major $428m
ACAM2000 smallpox vaccine contract with the US Centers for Disease Control and
Prevention and, more recently, a contract with the US National Institutes of
Allergy and Infectious Diseases (NIAID), part of the US National Institutes of
Health, to develop and supply a third-generation smallpox vaccine, MVA.

All of the commercial arrangements between the two companies remain in place
and are not affected by this sale. Moreover, Baxter and Acambis are
collaborating again to respond to a Request for Proposals recently issued by
the NIAID for a second MVA contract.

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Enquiries:

Acambis plc: Tel: [phone]

Dr John Brown, Chief Executive Officer

Gordon Cameron, Chief Financial Officer

Lyndsay Wright, Director of Communications

Financial Dynamics: Tel: [phone]

David Yates/ Charlie Armitstead

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 is developing a second-generation smallpox vaccine which is
currently undergoing clinical trials and, under a unique arrangement given the
threat of smallpox being used as a bioterrorist weapon, is manufacturing
emergency-use stockpiles of this investigational vaccine for the US Government
and other governments around the world. Acambis is establishing a travel
vaccines franchise through its US-based subsidiary Berna Products Corporation,
which markets Vivotif®, the world's only oral typhoid vaccine, in North
America. Acambis has a number of other potential travel vaccines in development
and is conducting clinical trials of vaccines against yellow fever, Japanese
encephalitis and dengue fever. Acambis recently became the first company to
start human clinical trials of a vaccine targeting the West Nile virus, which
has spread to 45 US States in the last four 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