<SEC-DOCUMENT>0001104659-25-094499.txt : 20250929
<SEC-HEADER>0001104659-25-094499.hdr.sgml : 20250929
<ACCEPTANCE-DATETIME>20250929162003
ACCESSION NUMBER:		0001104659-25-094499
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250925
FILED AS OF DATE:		20250929
DATE AS OF CHANGE:		20250929

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Durso Jerome Benedict
		CENTRAL INDEX KEY:			0001698665
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32587
		FILM NUMBER:		251356316

	MAIL ADDRESS:	
		STREET 1:		ALTIMMUNE, INC.
		STREET 2:		910 CLOPPER ROAD, SUITE 201S
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20878

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Altimmune, Inc.
		CENTRAL INDEX KEY:			0001326190
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				202726770
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		910 CLOPPER ROAD
		STREET 2:		SUITE 201S
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20878
		BUSINESS PHONE:		2406541450

	MAIL ADDRESS:	
		STREET 1:		910 CLOPPER ROAD
		STREET 2:		SUITE 201S
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20878

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	PHARMATHENE, INC
		DATE OF NAME CHANGE:	20071016

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	HEALTHCARE ACQUISITION CORP
		DATE OF NAME CHANGE:	20050505
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>tm2527377-8_4seq1.xml
<DESCRIPTION>OWNERSHIP DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-09-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001326190</issuerCik>
        <issuerName>Altimmune, Inc.</issuerName>
        <issuerTradingSymbol>ALT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001698665</rptOwnerCik>
            <rptOwnerName>Durso Jerome Benedict</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ALTIMMUNE, INC., 910 CLOPPER ROAD,</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 201S</rptOwnerStreet2>
            <rptOwnerCity>GAITHERSBURG</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>20878</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (option to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>3.92</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-09-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>48800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2035-09-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock, par value $0.0001</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>48800</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>48800</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares underlying the option become vested and exercisable in substantially equal monthly installments over the 12 months following September 25, 2025, subject to the reporting person's continued service through the applicable vesting date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Gregory Weaver, as Attorney-in-Fact</signatureName>
        <signatureDate>2025-09-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
