SCHEDULE 5

BLOCKLISTING SIX MONTHLY RETURN

1. Name of company: Acambis plc

2. Name of scheme: Acambis 1996 Approved Share Option Scheme

3. Period of return: From 01 January 2008 to 30 June 2008

4. Number and class of shares(s) (amount of stock/debt security) not issued under scheme at end of last period: 361,929

5. Number of shares issued/allotted under scheme during period: Nil

6. Balance under scheme not yet issued/allotted at end of period: 361,929

7. Number and class of share(s) (amount of stock/debt securities) originally listed and the date of admission: 33,916,280 ordinary shares of 10p each

Date of admission: 30 November 1995

Please confirm total number of shares in issue at the end of the period in order for us to update our records: 145,505,287

1. Name of company: Acambis plc

2. Name of scheme: Acambis 1995 Savings-Related Share Option Scheme

3. Period of return: From 01 January 2008 to 30 June 2008

4. Number and class of shares(s) (amount of stock/debt security) not issued under scheme at end of last period: 73,035

5. Number of shares issued/allotted under scheme during period: Nil

6. Balance under scheme not yet issued/allotted at end of period: 73,035

7. Number and class of share(s) (amount of stock/debt securities) originally listed and the date of admission: 33,916,280 ordinary shares of 10p each

Date of admission: 30 November 1995

Please confirm total number of shares in issue at the end of the period in order for us to update our records: 145,505,287

1. Name of company: Acambis plc

2. Name of scheme: Acambis 1999 Share Option Plan

3. Period of return: From 01 January 2008 to 30 June 2008

4. Number and class of shares(s) (amount of stock/debt security) not issued under scheme at end of last period:  127,909

5. Number of shares issued/allotted under scheme during period: Nil

6. Balance under scheme not yet issued/allotted at end of period: 127,909

7. Number and class of share(s) (amount of stock/debt securities) originally listed and the date of admission: 33,916,280 ordinary shares of 10p each

Date of admission: 30 November 1995

Please confirm total number of shares in issue at the end of the period in order for us to update our records: 145,505,287

1. Name of company: Acambis plc

2. Name of scheme: OraVax 1990 Stock Incentive Plan

3. Period of return: From 01 January 2008 to 30 June 2008

4. Number and class of shares(s) (amount of stock/debt security) not issued under scheme at end of last period: 143,706

5. Number of shares issued/allotted under scheme during period: Nil

6. Balance under scheme not yet issued/allotted at end of period: 143,706

7. Number and class of share(s) (amount of stock/debt securities) originally listed and the date of admission: 33,916,280 ordinary shares of 10p each

Date of admission: 30 November 1995

Please confirm total number of shares in issue at the end of the period in order for us to update our records: 145,505,287

1. Name of company: Acambis plc

2. Name of scheme: OraVax 1995 Stock Incentive Plan

3. Period of return: From 01 January 2008 to 30 June 2008

4. Number and class of shares(s) (amount of stock/debt security) not issued under scheme at end of last period: 104,179

5. Number of shares issued/allotted under scheme during period: Nil

6. Balance under scheme not yet issued/allotted at end of period: 104,179

7. Number and class of share(s) (amount of stock/debt securities) originally listed and the date of admission: 33,916,280 ordinary shares of 10p each

Date of admission: 30 November 1995

Please confirm total number of shares in issue at the end of the period in order for us to update our records: 145,505,287

1. Name of company: Acambis plc

2. Name of schemes: Acambis Share Incentive Plan, Acambis 2006 Approved Share Option Plan, Acambis 2006 Unapproved Share Option Plan, Acambis 2006 Deferred Bonus Plan

3. Period of return: From 01 January 2008 to 30 June 2008

4. Number and class of shares(s) (amount of stock/debt security) not issued under scheme at end of last period: Nil

5. Number of shares issued/allotted under scheme during period: 30,015

6. Balance under scheme not yet issued/allotted at end of period: 969,985

7. Number and class of share(s) (amount of stock/debt securities) originally listed and the date of admission: 33,916,280 ordinary shares of 10p each

Date of admission: 30 November 1995

Please confirm total number of shares in issue at the end of the period in order for us to update our records: 145,505,287

Contact for queries:                     Sarah Gowing
Address:                                    Acambis plc, Peterhouse Technology Park, 100 Fulbourn Road, 

                                                 Cambridge CB1 9PT
Name of person making return:    Sarah Gowing
Telephone:                                 01223 275300
Position of person making return: Company Secretary

Date of return:                            3 July 2008    

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