VaxGen Addresses MPM Claims in Letter to St...( Seeks to Correct the Record and...)

Seeks to Correct the Record and Provide Accurate Information to

Stockholders

SOUTH SAN FRANCISCO, Calif., Dec. 20 /PRNewswire-FirstCall/ -- VaxGen, Inc. (Pink Sheets: VXGN)

(Logo: http://www.newscom.com/cgi-bin/prnh/19991112/VAXGENLOGO)

Dear Stockholder:

As you are aware, VaxGen and Raven biotechnologies announced on November 12, 2007 that their respective Boards of Directors had unanimously approved the merger of the two companies, subject to stockholder approval.

As you may also have seen, MPM BioEquities Advisors, a VaxGen stockholder, sent a letter to me and VaxGen's Board on December 11, 2007. The content of this letter was subsequently disclosed by MPM in a press release on December 12th. We believe that this letter and press release contain errors, misstatements and incorrect assumptions which MPM has used to support its recommendation that VaxGen terminate the proposed merger, place its assets into a holding company, and pursue the sale or distribution of those assets; i.e., liquidation. The primary purpose of my letter to you is to correct the record, and to ensure that all stockholders have the necessary, accurate information in order to make an informed decision regarding the proposed merger. I also want to take the opportunity to comment on a number of issues that have arisen in my many conversations with stockholders over the last month.

MPM's analysis appears to reflect errors of three kinds:

1. It relies on very aggressive, indeed unrealistic, valuations of the

Company's non-financial assets, especially in a liquidation scenario,

and ignores the extensive process the Company and its advisors have

already undertaken over this past year seeking to monetize these

assets.

2. It fails to take full account of VaxGen's liabilities a
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