<SUBMISSION>
<ACCESSION-NUMBER>0001170961-07-000021
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20070307
<FILING-DATE>20070309
<DATE-OF-FILING-DATE-CHANGE>20070309
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>NOVAVAX INC
<CIK>0001000694
<ASSIGNED-SIC>2836
<IRS-NUMBER>222816046
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>508 LAPP ROAD
<CITY>MALVERN
<STATE>PA
<ZIP>19355
<PHONE>4849131200
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>508 LAPP ROAD
<CITY>MALVERN
<STATE>PA
<ZIP>19355
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>LAMBERT JOHN A
<CIK>0001229443
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-26770
<FILM-NUMBER>07685344
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>C/O CHIRON CORP
<STREET2>4560 HORTON STREET
<CITY>EMERYVILLE
<STATE>CA
<ZIP>94608-2916
<PHONE>5109232910
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-03-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001000694</issuerCik>
        <issuerName>NOVAVAX INC</issuerName>
        <issuerTradingSymbol>NVAX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001229443</rptOwnerCik>
            <rptOwnerName>LAMBERT JOHN A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NOVAVAX, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>9920 BELWARD CAMPUS DRIVE</rptOwnerStreet2>
            <rptOwnerCity>ROCKVILLE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>20850</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2007-03-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>100000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option - right to buy</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.77</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-03-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>250000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-03-07</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>250000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>250000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents a grant of 100,000 restricted stock units.  Each restricted stock unit represents a contingent right to receive one share of Novavax common stock.</footnote>
        <footnote id="F2">The restricted stock units vest in five separate tranches of 20,000 units:  (i) two tranches vest upon Novavax's achievement of certain performance criteria; (ii) one tranche vests upon Novavax's common stock achieving a market price of $6.00 per share; (iii) one tranche vests upon Novavax's common stock achieving a market price of $10.00 per share; and (iv) one tranche vests on March 7, 2010.  The entire award of restricted stock units to Mr. Lambert is contingent upon stockholder approval of an amendment (the &quot;Amendment&quot;) to Novavax's 2005 Stock Incentive Plan (the &quot;Plan&quot;) to increase the number of shares available for issuance under the Plan.  The Amendment was approved by Novavax's Board on March 7, 2007 and will be submitted to Novavax's stockholders for approval at Novavax's 2007 stockholders' meeting, which is scheduled for June 2007.</footnote>
        <footnote id="F3">The options vest in five separate tranches of 50,000 options:  (i) two tranches vest upon Novavax's achievement of certain performance criteria; (ii) one tranche vests upon Novavax's common stock achieving a market price of $6.00 per share; (iii) one tranche vests upon Novavax's common stock achieving a market price of $10.00 per share; and (iv) one tranche vests on March 7, 2010.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/Jeffrey W. Church, as attorney-in-fact for John A. Lambert</signatureName>
        <signatureDate>2007-03-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
