Exhibit 23.1
CONSENT OF INDEPENDENT REGISTERED PUBLIC
ACCOUNTING FIRM
We have issued our report dated March 12, 2007 (which report expresses an unqualified opinion and
includes an explanatory paragraph relating to the application of Statement of Financial Accounting
Standards No. 123(R) as of December 31, 2006), accompanying the consolidated financial statements
and managements assessment of the effectiveness of internal control over financial reporting
included in the Annual Report of Novavax, Inc. and Subsidiary on Form 10-K for the year ended
December 31, 2006 which are incorporated by reference in this Registration Statement. We consent
to the incorporation by reference in the Registration Statement of the aforementioned reports.
/s/ GRANT THORNTON LLP
Philadelphia, Pennsylvania
August 8, 2007