|   | 1. | The      H1N1 Product is a Product for Pandemic Flu for purposes of the      Agreement.  Notwithstanding the provisions of Section 3.1.4 of      the Agreement to the contrary but subject to paragraphs 2 and 3 below, no      milestone payment shall be due for receipt of [**********] of the H1N1      Product in Mexico for H1N1 influenza, and the milestone payment due within      thirty (30) days after [**********] of the H1N1 Product in Mexico for H1N1      influenza shall be [**********]. |
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|   | 2. | In      the event that the H1N1 Product receives [**********] for H1N1 influenza      in Mexico (the “Mexico Trigger Event”), in addition to the royalties      payable pursuant to Section 3.1.6 of the Agreement, Novavax shall pay or      cause to be paid to Wyeth, pursuant to Section 3.4 of the Agreement, a      separate royalty equal to [**********] of all [**********] of the H1N1      Product in Mexico for H1N1 influenza by Novavax or any of its Affiliates      or permitted sublicensees (such additional, separate royalty payments are      referred to as the “Additional Royalties”) until such time as Novavax and      its Affiliates and permitted sublicensees have paid to Wyeth Additional      Royalties in the aggregate amount of [**********], subject to paragraph 3      below. |
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|   | 3. | In      the event that the H1N1 Product receives [**********] for H1N1 influenza      in any jurisdiction other than Mexico at any time after the Mexico Trigger      Event when Novavax has paid to Wyeth Additional Royalties pursuant to      paragraph 2 above in an aggregate amount less than [**********], Novavax      shall, within thirty (30) days after such [**********], pay to Wyeth an      amount (the “H1N1 [**********] Makeup Amount”) equal to (a) [**********]      minus (b)      the aggregate amount of Additional Royalties paid to Wyeth pursuant to      paragraph 2 above through the date of such [**********].  Upon      payment of the H1N1 [**********] Makeup Amount, Novavax and its Affiliates      and permitted sublicenses shall have no further obligation to pay any      Additional Royalties to Wyeth. |
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|   | 4. | Nothing      herein shall affect the obligations of Novavax, its Affiliates and its      permitted sublicensees to make any payments to Wyeth under Section 3.1.3      or 3.1.4 of the Agreement for any Product other than the H1N1 Product or      for any indication for the H1N1 Product other than H1N1      influenza. |
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|   | 5. | In      all other respects the Agreement shall remain in full force and      effect. |
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| NOVAVAX,      INC.                                    |              | WYETH      HOLDINGS                                     |
|-------------------------------------------------------|-------------------|---------------------------------------------------------|
|                                                  |              | CORPORATION                                             |
|                                                  |              |                                                    |   |   |
| By:                                                   | /s/ Rahul Singhvi |                                                    | By: | /s/ Arthur J. Cohn |
|                                                  |              |                                                    |   |   |
| Name:        Rahul Singhvi, Sc.D.           |              | Name:   Arthur      J. Cohn              |
|                                                  |              |                                                    |
| Title:          President and CEO |              | Title:     Vice      President |

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