COMMON STOCK PURCHASE WARRANT

Exhibit 4.1

COMMON STOCK PURCHASE WARRANT

To Purchase                      Shares of Common Stock of

Novavax, Inc.

     THIS COMMON STOCK PURCHASE WARRANT CERTIFIES that, for value received,                      (the “ Holder ”), is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any time on or after January 31, 2009 (the six month anniversary of the issue date) (the “ Initial Exercise Date ”) and on or prior to the close of business on July 31, 2013 (the “ Termination Date ”) but not thereafter, to subscribe for and purchase from Novavax, Inc., a corporation incorporated in the State of Delaware (the “ Company ”), up to                                  shares (the “ Warrant Shares ”) of Common Stock, par value $0.01 per share, of the Company (the “ Common Stock ”). The purchase price of one share of Common Stock (the “ Exercise Price ”) under this Warrant shall be $3.62, subject to adjustment hereunder. The Exercise Price and the number of Warrant Shares for which the Warrant is exercisable shall be subject to adjustment as provided herein. Capitalized terms used and not otherwise defined in their initial use shall have the meanings set forth in Section 17 herein .

     1.  Title to Warrant . Prior to the Termination Date and subject to compliance with applicable laws and Section 7 of this Warrant, this Warrant and all rights hereunder are transferable, in whole or in part, at the office or agency of the Company by the Holder in person or by duly authorized attorney, upon surrender of this Warrant together with the Assignment Form annexed hereto properly endorsed.

     2.  Authorization of Shares . The Company covenants that all Warrant Shares which may be issued upon the exercise of the purchase rights represented by this Warrant will, upon exercise of the purchase rights represented by this Warrant, be duly authorized, validly issued, fully paid and nonassessable and free from all taxes, liens and charges in respect of the issue thereof (other than taxes in respect of any transfer occurring contemporaneously with such issue) and such Warrant Shares will not be subject to any statutory or contractual preemptive rights or other rights to subscribe for or purchase or acquire any shares of Common Stock, which have not been waived or complied with.

     3.  Exercise of Warrant .

          (a) Exercise of the purchase rights represented by this Warrant may be made at any time or times on or after the Initial Exercise Date and on or before the Termination Date by the delivery of the Notice of Exercise Form annexed hereto duly executed, and the surrender of this Warrant to follow within three (3) Trading Days thereafter at the office of the Company (or such other office or agency of the Company as it may designate by notice in writing to the registered Holder at the address of such Holder appearing on the books of the Company) and upon payment of the Exercise Price of the shares thereby purchased by wire transfer or cashier’s check drawn on a United States bank or by means of a cashless exercise pursuant to Section 3(d), the Holder shall be entitled to receive a certificate for the number of Warrant Shares so purchased. Certificates for shares purchased hereunder shall be delivered to the Holder within three (3) Trading Days after the date on which this Warrant shall have been exercised as

aforesaid, provided that, if the Company is able to do so, it will deliver the shares electronically through the facilities of the Depository Trust Company’s DWAC System, or any similar successor system. This Warrant shall be deemed to have been exercised and such certificate or certificates shall be deemed to have been issued, and the Holder or any other person so designated to be named therein shall be deemed to have become a holder of record of such shares for all purposes, as of the date the Warrant has been exercised by payment to the Company of the Exercise Price and all taxes required to be paid by the Holder, if any, pursuant to Section 5 prior to the issuance of such shares, have been paid. If the Company fails to deliver to the Holder a certificate or certificates representing the Warrant Shares pursuant to this Section 3(a) by the close of business on the third Trading Day after the date of exercise, then the Holder will have the right to rescind such exercise. In addition to any other rights available to the Holder, if the Company fails to deliver to the Holder a certificate or certificates representing the Warrant Shares pursuant to an exercise by the close of business on the third Trading Day after the date of exercise, and if after such third Trading Day the Holder is required by its broker to purchase, or if the broker purchases (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a “ Buy In ”), then the Company shall (1) pay in cash to the Holder the amount by which (x) the Holder’s total purchase price (including brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (A) the number of Warrant Shares that the Company was required to deliver to the Holder in connection with the exercise at issue times (B) the price at which the sell order giving rise to such purchase obligation was executed, and (2) at the option of the Holder, either reinstate the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was not honored or deliver to the Holder the number of shares of Common Stock that would have been issued had the Company timely complied with its exercise and delivery obligations hereunder. For example, if the Holder purchases Common Stock having a total purchase price of $11,000 to cover a Buy In with respect to an attempted exercise of shares of Common Stock with an aggregate sale price giving rise to such purchase obligation of $10,000, under clause (1) of the immediately preceding sentence the Company shall be required to pay the Holder $1,000. The Holder shall provide the Company written notice indicating the amounts payable to the Holder in respect of the Buy In, together with applicable confirmations. Nothing herein shall limit a Holder’s right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company’s failure to timely deliver certificates representing shares of Common Stock upon exercise of the Warrant as required pursuant to the terms hereof.

          (b) If this Warrant shall have been exercised in part, the Company shall, at the time of delivery of the certificate or certificates representing Warrant Shares, deliver to Holder a new Warrant evidencing the rights of Holder to purchase the unpurchased Warrant Shares called for by this Warrant, which new Warrant shall in all other respects be identical with this Warrant.

          (c) Notwithstanding anything in this Warrant to the contrary, the Holder shall not have the right to exercise any portion of this Warrant, pursuant to Section 3(a) or otherwise, to the extent that either before or after giving effect to such issuance after exercise, the Holder (together with the Holder’s Affiliates), as set forth on the applicable Notice of Exercise, would beneficially own in excess of 9.99% of the number of shares of the Common Stock outstanding immediately after giving effect to such issuance. For purposes of the foregoing sentence, the

number of shares of Common Stock beneficially owned by the Holder and its Affiliates shall include the number of shares of Common Stock issuable upon exercise of this Warrant with respect to which the determination of such sentence is being made, but shall exclude the number of shares of Common Stock which would be issuable upon (1) exercise of the remaining, nonexercised portion of this Warrant beneficially owned by the Holder or any of its Affiliates and (2) exercise or conversion of the unexercised or nonconverted portion of any other securities of the Company (including, without limitation, any other Warrants) subject to a limitation on conversion or exercise analogous to the limitation contained herein beneficially owned by the Holder or any of its Affiliates. Except as set forth in the preceding sentence, for purposes of this Section 3(c), beneficial ownership shall be calculated in accordance with Section 13(d) of the Exchange Act. For purposes of this Section 3(c), in determining the number of outstanding shares of Common Stock, the Holder may rely on the number of outstanding shares of Common Stock as reflected in (x) the Company’s most recent Form 10-Q or Form 10-K, as the case may be, (y) a more recent public announcement by the Company or (z) any other written notice by the Company or the Company’s transfer agent setting forth the number of shares of Common Stock outstanding. Upon the written or oral request of the Holder, the Company shall within two Trading Days confirm orally and in writing to the Holder the number of shares of Common Stock then outstanding. In any case, the number of outstanding shares of Company Common Stock shall be determined after giving effect to the conversion or exercise of securities of the Company, including this Warrant, by the Holder or its Affiliates since the date as of which such number of outstanding shares of Common Stock was reported. By written notice to the Company, the Holder may waive the provisions of this Section but any such waiver will not be effective until the 61st day after such notice is delivered to the Company, nor will any such waiver effect any other Holder.

          (d) This Warrant may be exercised by means of a “cashless exercise” in which the Holder shall be entitled to receive a certificate for the number of Warrant Shares equal to the quotient obtained by dividing [(A-B) (X)] by (A), where:

     4.  No Fractional Shares or Scrip . No fractional shares or scrip representing fractional shares shall be issued upon the exercise of this Warrant. As to any fraction of a share which Holder would otherwise be entitled to purchase upon such exercise, the Company shall pay a cash adjustment in respect of such final fraction in an amount equal to such fraction multiplied by the Exercise Price.

     5.  Charges, Taxes and Expenses . Issuance of certificates for Warrant Shares shall be made without charge to the Holder for any issue or transfer tax or other incidental expense in respect of the issuance of such certificate, all of which taxes and expenses shall be paid by the

Company, and such certificates shall be issued in the name of the Holder or in such name or names as may be directed by the Holder; provided, however, that in the event certificates for Warrant Shares are to be issued in a name other than the name of the Holder, this Warrant when surrendered for exercise shall be accompanied by the Assignment Form attached hereto duly executed by the Holder; and the Company may require, as a condition thereto, the payment of a sum sufficient to reimburse it for any transfer tax incidental thereto.

     6.  Closing of Books . The Company will not close its stockholder books or records in any manner which prevents the timely exercise of this Warrant, pursuant to the terms hereof.

     7.  Transfer, Division and Combination .

          (a) Subject to compliance with any applicable securities laws and the conditions set forth in Sections 1 and 7(e) hereof, this Warrant and all rights hereunder are transferable, in whole or in part, so long as the amount of Warrant Shares obtainable upon exercise of the portion of the Warrant so transferred is equal to the lesser of 50,000 shares or the total number of Warrant Shares represented by such Warrant), upon surrender of this Warrant at the principal office of the Company, together with a written assignment of this Warrant substantially in the form attached hereto duly executed by the Holder or its agent or attorney and funds sufficient to pay any transfer taxes payable upon the making of such transfer. Upon such surrender and, if required, such payment, the Company shall execute and deliver a new Warrant or Warrants in the name of the assignee or assignees and in the denomination or denominations specified in such instrument of assignment, and shall issue to the assignor a new Warrant evidencing the portion of this Warrant not so assigned, and this Warrant shall promptly be cancelled. A Warrant, if properly assigned, may be exercised by a new holder for the purchase of Warrant Shares without having a new Warrant issued.

          (b) This Warrant may be divided or combined with other Warrants upon presentation hereof at the aforesaid office of the Company, together with a written notice specifying the names and denominations in which new Warrants are to be issued, signed by the Holder or its agent or attorney. Subject to compliance with Section 7(a), as to any transfer which may be involved in such division or combination, the Company shall execute and deliver a new Warrant or Warrants in exchange for the Warrant or Warrants to be divided or combined in accordance with such notice.

          (c) The Company shall prepare, issue and deliver at its own expense (other than transfer taxes) the new Warrant or Warrants under this Section 7.

          (d) The Company agrees to maintain, at its aforesaid office, books for the registration and the registration of transfer of the Warrants.

          (e) If, at the time of the surrender of this Warrant in connection with any transfer of this Warrant, the transfer of this Warrant shall not be registered pursuant to an effective registration statement under the Securities Act and under applicable state securities or blue sky laws, the Company may require, as a condition of allowing such transfer (i) that the Holder or transferee of this Warrant, as the case may be, furnish to the Company a written opinion of counsel (which opinion shall be in form, substance and scope customary for opinions

of counsel in comparable transactions) to the effect that such transfer may be made without registration under the Securities Act and under applicable state securities or blue sky laws, (ii) that the holder or transferee execute and deliver to the Company an investment letter in form and substance acceptable to the Company and (iii) that the transferee be an “accredited investor” as defined in Rule 501(a) promulgated under the Securities Act.

     8.  No Rights as Shareholder until Exercise . This Warrant does not entitle the Holder to any voting rights or other rights as a shareholder of the Company with respect to the Warrant Shares prior to the exercise hereof. Upon the surrender of this Warrant and the payment of the aggregate Exercise Price (or by means of a cashless exercise), the Warrant Shares so purchased shall be and be deemed to be issued to such Holder as the record owner of such shares as of the close of business on the later of the date of such surrender or, if applicable, payment.

     9.  Loss, Theft, Destruction or Mutilation of Warrant . The Company covenants that upon receipt by the Company of e