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                                                                  EXHIBIT 10.13


                                 NOVAVAX, INC.
                               8320 Guilford Road
                           Columbia, Maryland 21046
                                        
                                        
                               February 19, 1998

Dr. Thomas G. Tachovsky
39 Riverside Terrace
North Easton, MA 02356

Dear Tom:

     On behalf of Novavax, Inc. (the "Company"), I am pleased to offer you the
position of Vice President, Business Development of the Company, effective
February 23, 1998. We are greatly looking forward to your joining the 
Company's team.

     Job Title:  Vice President, Business Development.

     Salary:  $130,000 per year payable in accordance with the Company's 
payroll policies in effect from time to time.

     Bonus Program:  You will be entitled to participate in a bonus program if
the Company hereafter establishes one for the benefit of senior executives and
other employees of the Company, under which award payments, if any, will be
based on performance criteria and milestones to be mutually determined by the
Company and you.

     Stock Options:  The Company will grant you stock options to purchase
75,000 shares of the Company's Common Stock ($.01 par value) at an exercise
price equal to the closing price of the Company's Common Stock on the date of
grant, February 11, 1998. The options will vest as to one-third of the shares 
on the six-month anniversary of the date of grant, as to an additional
one-third of the shares on the eighteenth-month anniversary of the date of
grant and as to the final one-third of the shares on the thirty-month
anniversary of the date of grant. You will be eligible to be granted additional
options from time to time, based on your job performance.

     Benefits:  The Company will provide medical and dental benefits, life
insurance, and disability insurance in accordance with the Company's policies
in effect from time to time. As of the date of this letter, the Company
currently pays 100% of family coverage as provided by the Company's group
medical insurer, 100% of the premium for $130,000 of life insurance under the
Company's group life insurance plan and 100% of the premium for the Company's
long-term disability insurance.

     Vacation:  You will be entitled to three weeks of vacation time per year,
calculated on a calendar year basis in accordance with the Company's policies in
effect from time to time.

     Employment Requirements and Term:  You will be required by the Company to
sign the Company's standard form of Non-Disclosure Agreement and sign and
acknowledge certain Company policies as a condition to your employment by the
Company. In addition, it is a requirement that the Company and you negotiate and
sign an Employment Agreement which, among other things, will provide for a one
year term of employment, a six month noncompetition period following
termination of employment and severance pay of six months' salary in the event
of an early termination of employment without cause.  
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Dr. Thomas G. Tachovsky
February 19, 1998
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     Entire Agreement:  This agreement sets forth the entire agreement and
understanding between you and the Company regarding all subjects covered
herein, the terms of which may not be changed or modified except by agreement
in writing signed by you and the Company.

     Severability:  Should any provision of this agreement, or portion thereof,
be found invalid and unenforceable, the remaining provisions shall continue in
full force and effect.

     Governing Law:  This agreement shall be governed, construed and enforced
in accordance with the laws of Delaware, without regard to principles of
conflict of law.

     Conflict:  You hereby acknowledge that you are not a party to any
agreement that in any way prohibits or imposes any restriction on your 
employment with the Company, and your acceptance hereof will not breach any
agreement to which you are a party.

     Please acknowledge your acceptance of this offer by signing the copy of
this letter and returning it to me.


                                   Very truly yours,


                                   /s/ RICHARD F. MARADIE

                                   Richard F. Maradie,
                                   President and Chief Executive Officer


ACCEPTED: (as annotated)


/s/ THOMAS G. TACHOVSKY
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Thomas G. Tachovsky