Exhibit 3.1

FIFTH Amended and Restated CERTIFICATE OF INCORPORATION 

OF 

ICOSAVAX, INC.

FIRST: The name of the corporation is Icosavax, Inc. (the “Corporation”).

SECOND: The address of the Corporation’s registered office in the State of Delaware is Corporation Trust Center, 1209 Orange Street, City of Wilmington, County of New Castle, Delaware 19801. The name of the Corporation’s registered agent at such address is The Corporation Trust Company.

THIRD: The purpose of the Corporation is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of the State of Delaware (the “DGCL”).

FOURTH: The total number of shares of stock which the corporation is authorized to issue is 1,000 shares of common stock, having a par value of $0.01 per share.

FIFTH: The business and affairs of the Corporation shall be managed by or under the direction of the board of directors, and the directors need not be elected by ballot unless required by the bylaws of the Corporation.

SIXTH: In furtherance and not in limitation of the powers conferred by the laws of the State of Delaware, the board of directors is expressly authorized to adopt, amend or repeal the bylaws of the Corporation.

SEVENTH: No director or officer of the Corporation shall have any personal liability to the Corporation or its stockholders for monetary damages for any breach of fiduciary duty as a director or officer, as applicable, except to the extent such exemption from liability or limitation thereof is not permitted under the DGCL as the same exists or hereafter may be amended. Any amendment, repeal or modification of this Article SEVENTH, or the adoption of any provision of the Fifth Amended and Restated Certificate inconsistent with this Article SEVENTH, shall not adversely affect any right or protection of a director or officer of the Corporation with respect to any act or omission occurring prior to such amendment, repeal, modification or adoption. If the DGCL is amended after approval by the stockholders of this Article SEVENTH to authorize corporate action further eliminating or limiting the personal liability of directors or officers, then the liability of a director or officer of the Corporation, as applicable, shall be eliminated or limited to the fullest extent permitted by the DGCL as so amended.

EIGHTH: The Corporation shall have the power to provide rights to indemnification and advancement of expenses to its current and former officers, directors, employees and agents and to any person who is or was serving at the request of the Corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise.

NINTH: Subject to Article SEVENTH, the Corporation reserves the right to amend, repeal and/or eliminate any provision contained in this Certificate of Incorporation in the manner from time to time prescribed by the laws of the State of Delaware. All rights herein conferred are granted subject to this reservation.

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