Exhibit 4.3



 


[Form
of Warrant Certificate]


 


[FACE]


 


Number


 


Warrants


 


THIS
WARRANT SHALL BE VOID IF NOT EXERCISED PRIOR TO

THE EXPIRATION OF THE EXERCISE PERIOD PROVIDED FOR

IN THE WARRANT AGREEMENT DESCRIBED BELOW


 


MSD
ACQUISITION CORP.


 


Incorporated
Under the Laws of the Cayman Islands


 


CUSIP
[●]


 


Warrant
Certificate


 


This
Warrant Certificate certifies that                ,
or registered assigns, is the registered holder of                
warrant(s) (the “Warrants” and each, a “Warrant”) to purchase Class A ordinary
shares, $0.0001 par value (“Ordinary Shares”), of MSD Acquisition Corp., a Cayman Islands exempted company
(the “Company”). Each Warrant entitles the holder, upon exercise during the period set forth in the
Warrant Agreement referred to below, to receive from the Company that number of fully paid and nonassessable Ordinary Shares as
set forth below, at the exercise price (the “Exercise Price”) as determined pursuant to the Warrant
Agreement, payable in lawful money (or through “cashless exercise” as provided for in the Warrant Agreement)
of the United States of America upon surrender of this Warrant Certificate and payment of the Exercise Price at the office or
agency of the Warrant Agent referred to below, subject to the conditions set forth herein and in the Warrant Agreement. Defined
terms used in this Warrant Certificate but not defined herein shall have the meanings given to them in the Warrant Agreement.


 


Each
whole Warrant is initially exercisable for one fully paid and non-assessable Ordinary Share. Fractional shares shall not be issued
upon exercise of any Warrant. If, upon the exercise of Warrants, a holder would be entitled to receive a fractional interest in
an Ordinary Share, the Company shall, upon exercise, round down to the nearest whole number the number of Ordinary Shares to be
issued to the Warrant holder. The number of Ordinary Shares issuable upon exercise of the Warrants is subject to adjustment upon
the occurrence of certain events as set forth in the Warrant Agreement.


 


The
initial Exercise Price per one Ordinary Share for any Warrant is equal to $11.50 per share. The Exercise Price is subject to adjustment
upon the occurrence of certain events as set forth in the Warrant Agreement.


 


Subject
to the conditions set forth in the Warrant Agreement, the Warrants may be exercised only during the Exercise Period and to the
extent not exercised by the end of such Exercise Period, such Warrants shall become void. The Warrants may be redeemed, subject
to certain conditions, as set forth in the Warrant Agreement.


 


Reference
is hereby made to the further provisions of this Warrant Certificate set forth on the reverse hereof and such further provisions
shall for all purposes have the same effect as though fully set forth at this place.


 


This
Warrant Certificate shall not be valid unless countersigned by the Warrant Agent, as such term is used in the Warrant Agreement.
This Warrant Certificate shall be governed by and construed in accordance with the internal laws of the State of New York.


 




     


     


    

 


	 	MSD ACQUISITION CORP.
	 	 
	 	By:	 	 
	 	 	Name:  	John Cardoso
	 	 	Title:	Chief Financial Officer



 


	 	CONTINENTAL STOCK TRANSFER &

 TRUST COMPANY, AS WARRANT AGENT
	 	 
	 	By:	 
	 	Name:  	                   
	 	Title:	 



 






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[Form
of Warrant Certificate]


 


[Reverse]


 


The
Warrants evidenced by this Warrant Certificate are part of a duly authorized issue of Warrants entitling the holder on exercise
to receive Ordinary Shares and are issued or to be issued pursuant to a Warrant Agreement dated as of February          , 2021 (the “Warrant
Agreement”), duly executed and delivered by the Company to Continental Stock Transfer & Trust Company, a New
York corporation, as warrant agent (the “Warrant Agent”), which Warrant Agreement is hereby incorporated
by reference in and made a part of this instrument and is hereby referred to for a description of the rights, limitation of rights,
obligations, duties and immunities thereunder of the Warrant Agent, the Company and the holders (the words “holders”
or “holder” meaning the Registered Holders or Registered Holder, respectively) of the Warrants. A copy
of the Warrant Agreement may be obtained by the holder hereof upon written request to the Company. Defined terms used in this
Warrant Certificate but not defined herein shall have the meanings given to them in the Warrant Agreement.


 


Warrants
may be exercised at any time during the Exercise Period set forth in the Warrant Agreement. The holder of Warrants evidenced by
this Warrant Certificate may exercise them by surrendering this Warrant Certificate, with the form of Election to Purchase set
forth hereon properly completed and executed, together with payment of the Exercise Price as specified in the Warrant Agreement
(or through “cashless exercise” as provided for in the Warrant Agreement) at the principal corporate trust
office of the Warrant Agent. In the event that upon any exercise of Warrants evidenced hereby the number of Warrants exercised
shall be less than the total number of Warrants evidenced hereby, there shall be issued to the holder hereof or his, her or its
assignee, a new Warrant Certificate evidencing the number of Warrants not exercised.


 


Notwithstanding
anything else in this Warrant Certificate or the Warrant Agreement, no Warrant may be exercised unless at the time of exercise
(i) a registration statement covering the issuance of the Ordinary Shares to be issued upon exercise is effective under the Securities
Act and (ii) a prospectus thereunder relating to the Ordinary Shares is current, except through “cashless exercise”
as provided for in the Warrant Agreement.


 


The
Warrant Agreement provides that upon the occurrence of certain events the number of Ordinary Shares issuable upon exercise of
the Warrants set forth on the face hereof may, subject to certain conditions, be adjusted. If, upon exercise of a Warrant, the
holder thereof would be entitled to receive a fractional interest in an Ordinary Share, the Company shall, upon exercise, round
down to the nearest whole number of Ordinary Shares to be issued to the holder of the Warrant.


 


Warrant
Certificates, when surrendered at the principal corporate trust office of the Warrant Agent by the Registered Holder thereof in
person or by legal representative or attorney duly authorized in writing, may be exchanged, in the manner and subject to the limitations
provided in the Warrant Agreement, but without payment of any service charge, for another Warrant Certificate or Warrant Certificates
of like tenor evidencing in the aggregate a like number of Warrants.


 


Upon
due presentation for registration of transfer of this Warrant Certificate at the office of the Warrant Agent a new Warrant Certificate
or Warrant Certificates of like tenor and evidencing in the aggregate a like number of Warrants shall be issued to the transferee(s)
in exchange for this Warrant Certificate, subject to the limitations provided in the Warrant Agreement, without charge except
for any tax or other governmental charge imposed in connection therewith.


 


The
Company and the Warrant Agent may deem and treat the Registered Holder(s) hereof as the absolute owner(s) of this Warrant Certificate
(notwithstanding any notation of ownership or other writing hereon made by anyone), for the purpose of any exercise hereof, of
any distribution to the holder(s) hereof, and for all other purposes, and neither the Company nor the Warrant Agent shall be affected
by any notice to the contrary. Neither the Warrants nor this Warrant Certificate entitles any holder hereof to any rights of a
shareholder of the Company.


 




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Election
to Purchase


 


(To
Be Executed Upon Exercise of Warrant)


 


The
undersigned hereby irrevocably elects to exercise the right, represented by this Warrant Certificate, to receive        
Ordinary Shares and herewith tenders payment for such Ordinary Shares to the order of MSD Acquisition Corp. (the “Company”)
in the amount of $        in accordance with the terms hereof. The undersigned requests that
a certificate for such Ordinary Shares be registered in the name of               ,
whose address is                and that such Ordinary Shares
be delivered to                whose address is               .
If said         number of Ordinary Shares is less than all of the Ordinary Shares purchasable
hereunder, the undersigned requests that a new Warrant Certificate representing the remaining balance of such Ordinary Shares
be registered in the name of               , whose address
is                and that such Warrant Certificate be delivered
to               , whose address is               .


 


In
the event that the Warrant has been called for redemption by the Company pursuant to Section 6.2 of the Warrant Agreement
and a holder thereof elects to exercise its Warrant pursuant to a Make-Whole Exercise, the number of Ordinary Shares that this
Warrant is exercisable for shall be determined in accordance with subsection 3.3.1(b) or Section 6.2 of the Warrant
Agreement, as applicable.


 


In
the event that the Warrant is a Private Placement Warrant that is to be exercised on a “cashless” basis pursuant to
subsection 3.3.1(b) of the Warrant Agreement, the number of Ordinary Shares that this Warrant is exercisable for shall
be determined in accordance with subsection 3.3.1(b) of the Warrant Agreement.


 


In
the event that the Warrant is to be exercised on a “cashless” basis pursuant to Section 7.4 of the Warrant
Agreement, the number of Ordinary Shares that this Warrant is exercisable for shall be determined in accordance with Section
7.4 of the Warrant Agreement.


 


In
the event that the Warrant may be exercised, to the extent allowed by the Warrant Agreement, through cashless exercise (i) the
number of Ordinary Shares that this Warrant is exercisable for would be determined in accordance with the relevant section of
the Warrant Agreement which allows for such cashless exercise and (ii) the holder hereof shall complete the following: The undersigned
hereby irrevocably elects to exercise the right, represented by this Warrant Certificate, through the cashless exercise provisions
of the Warrant Agreement, to receive Ordinary Shares. If said number of shares is less than all of the Ordinary Shares purchasable
hereunder (after giving effect to the cashless exercise), the undersigned requests that a new Warrant Certificate representing
the remaining balance of such Ordinary Shares be registered in the name of               ,
whose address is                and that such Warrant Certificate
be delivered to              , whose address is               .


 


 


[Signature
Page Follows]


 




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	Date:          	 
	 	 
	 	(SIGNATURE)
	 	 
	 	(ADDRESS)

	 	 
	 	(TAX IDENTIFICATION NUMBER)


  


Signature
Guaranteed:


 


THE
SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND
CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15 UNDER THE
SECURITIES EXCHANGE ACT OF 1934, AS AMENDED).


 



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