EXHIBIT 23.1

               Consent of Ernst & Young LLP, Independent Auditors

We consent to the incorporation by reference in the Registration Statement
(Form S-8) pertaining to the 1999 Non-Officer Equity Incentive Plan of Aviron
of our report dated January 25, 2001, with respect to the consolidated
financial statements of Aviron included in its Annual Report (Form 10-K) for
the year ended December 31, 2000, filed with the Securities and Exchange
Commission.

                                                           /s/ Ernst & Young LLP

Palo Alto, California
October 19, 2001