8-K

   1
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D. C. 20549

                                    FORM 8-K

                                 CURRENT REPORT


                     Pursuant to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934


       Date of Report (Date of earliest event reported): January 12, 1999



                                     AVIRON
             (Exact name of registrant as specified in its charter)


                                    DELAWARE
                 (State or other jurisdiction of incorporation)



           0-20815                                   77-0309686
     (Commission File No.)                (IRS Employer Identification No.)



                             297 N. BERNARDO AVENUE
                             MOUNTAIN VIEW, CA 94043
              (Address of principal executive offices and zip code)



       Registrant's telephone number, including area code: (650) 919-6500



   2
ITEM 5.   OTHER EVENTS.

On January 12, 1999, Wyeth Lederle Vaccines, a business unit of Wyeth-Ayerst
Laboratories, the pharmaceutical division of American Home Products Corporation,
and Aviron announced a worldwide collaboration for the marketing of FluMist(TM),
Aviron's investigational intranasal influenza vaccine. See the Company's press
releases, attached hereto as Exhibit 99.1 and Exhibit 99.2.

ITEM 7.   EXHIBITS.

Exhibit 99.1    Press Release, dated January 12, 1999, entitled "Wyeth Lederle
                Vaccines and Aviron Enter Into Global Collaboration on
                FluMist(TM) - Agreement for Co-Promotion and International
                Marketing Rights."

Exhibit 99.2    Press Release, dated January 12, 1999, entitled "Aviron Provides
                Additional Information about Global Collaboration on FluMist(TM)
                with Wyeth Lederle Vaccines."


                                       1


   3
                                    SIGNATURE

               Pursuant to the requirements of the Securities Exchange Act of
1934, the registrant has duly caused this report to be signed on its behalf by
the undersigned, hereunto duly authorized.


                                        AVIRON


Dated:  January 20, 1999           By:  /s/ J. Leighton Read, M.D.
                                      -----------------------------------------
                                            J. Leighton Read, M.D.
                                            Chairman and Chief Executive Officer


                                       2


   4
                                INDEX TO EXHIBITS

Exhibit 99.1            Press Release, dated January 12, 1999, entitled "Wyeth
                        Lederle Vaccines and Aviron Enter Into Global
                        Collaboration on FluMist(TM) - Agreement for
                        Co-Promotion and International Marketing Rights."

Exhibit 99.2            Press Release, dated January 12, 1999, entitled "Aviron
                        Provides Additional Information about Global
                        Collaboration on FluMist(TM) with Wyeth Lederle
                        Vaccines."

EX-99.1

   1
EXHIBIT 99.1

WYETH LEDERLE VACCINES AND AVIRON ENTER INTO GLOBAL COLLABORATION ON FLUMIST(TM)
AGREEMENT FOR CO-PROMOTION AND INTERNATIONAL MARKETING RIGHTS


ST. DAVIDS, PA AND MOUNTAIN VIEW, CA - JANUARY 12, 1999 - Wyeth Lederle
Vaccines, a business unit of Wyeth-Ayerst Laboratories, (the pharmaceutical
division of American Home Products Corporation - NYSE:AHP) and Aviron (Nasdaq:
AVIR) today announced a worldwide collaboration for the marketing of FLUMIST(TM)
- - Aviron's investigational intranasal influenza vaccine. FluMist(TM) is under
development for the prevention of influenza and its associated complications and
has completed pivotal phase III clinical trials. The agreement is subject to
Hart-Scott-Rodino review.

Under the agreement, Aviron is granting Wyeth Lederle Vaccines exclusive
worldwide rights to market FLUMIST(TM). Wyeth Lederle Vaccines and Aviron will
co-promote FLUMIST(TM) in the U.S., while Wyeth will have the exclusive right to
market the product ex-U.S. In each case, Wyeth will hold the marketing rights
for up to eleven (11) years. The collaboration excludes Korea, Australia, New
Zealand and certain South Pacific countries. The companies will collaborate on
the regulatory, clinical, and marketing programs for the product.

"We believe Wyeth Lederle's leadership and depth of experience in the vaccine
industry, together with Wyeth-Ayerst's global reach, will accelerate and broaden
delivery of FLUMIST(TM) to all who may benefit from this important future
influenza vaccine," says J. Leighton Read, MD, Aviron's Chairman and Chief
Executive Officer.

Each year, influenza affects an estimated 75 to 150 million people worldwide. In
the U.S., the disease results in an estimated 150,000 hospitalizations and over
20,000 deaths annually. According to the American Lung Association, 90 million
workdays were lost to the flu last year in the U.S. Children lose over 30
million school days each year due to influenza and its associated complications.

"Once approved, FLUMIST(TM) will strengthen our core respiratory tract infection
franchise which includes our pneumococcal vaccine, now in development - by
expanding the use of flu vaccines in new patient groups," says Bernard Poussot,
President, Wyeth-Ayerst Global Pharmaceuticals.

Aviron is a biopharmaceutical company based in Mountain View, CA focused on
prevention of disease. The company's goal is to develop products that offer
cost-effective prevention of a wide range of infections that affect the general
population. The majority of Aviron's products under development are live
vaccines against viral infections. FLUMIST(TM) is the company's lead vaccine
candidate. Aviron plans to submit its license application for FLUMIST(TM) to the
FDA later in 1999.

Wyeth Lederle Vaccines is a business unit of Wyeth-Ayerst Laboratories, the
pharmaceutical division of American Home Products Corporation (NYSE:AHP).
Wyeth-Ayerst is a major research-oriented pharmaceutical company with leading
products in the areas of women's health 


   2
care, cardiovascular disease therapies, central nervous system drugs,
anti-inflammatory agents, vaccines, and generic pharmaceuticals. American Home
Products Corporation is one of the world's largest research-based pharmaceutical
and health care products companies. It is a leader in the discovery,
development, manufacturing, and marketing of prescription drugs and
over-the-counter medications. It is also a leader in vaccines, biotechnology,
agricultural products, and animal health care.

The statements in this press release that are not historical facts are
forward-looking statements that involve risks and uncertainties including,
without limitation, risks associated with the inherent uncertainty of
pharmaceutical research, product development and commercialization, and the
impact of competitive products and patents. Factors relating to Aviron that
could cause actual results to differ materially include, but are not limited to
failure to receive regulatory approval for the marketing of FLUMIST(TM) or to
receive payments under collaborative agreements that are contingent upon future
events that may or may not occur. Sales of FLUMIST(TM) and future payments to
Aviron are dependent upon the successful development, manufacturing, supply,
sale and distribution of the product by Aviron, its third party suppliers and
Wyeth Lederle. Risks and uncertainties also include those detailed from time to
time in AHP's and Aviron's periodic reports filed with the Securities and
Exchange Commission including Quarterly Reports on Form 10-Q and Annual Reports
on Form 10-K and Form 20-F. Actual results may differ from the forward-looking
statements.

EX-99.2

   1
Exhibit 99.2

AVIRON PROVIDES ADDITIONAL INFORMATION ABOUT GLOBAL COLLABORATION ON FLUMIST(TM)
WITH WYETH LEDERLE VACCINES


MOUNTAIN VIEW, CA - JANUARY 12, 1999 - Aviron (Nasdaq: AVIR) is providing
additional information regarding the transaction announced earlier today between
the company and Wyeth Lederle Vaccines for the marketing of FLUMIST(TM) --
Aviron's investigational intranasal influenza vaccine.

As consideration under the agreement, which is subject to Hart-Scott-Rodino
review, Aviron will receive cash payments of $15 million for the initial
license, $15 million upon acceptance for filing with the U.S. Food and Drug
Administration (FDA), and $20 million upon FDA marketing approval for
FLUMIST(TM). Compensation for achieving additional development and regulatory
milestones is included in the agreement terms. The granting of certain other
rights under the license would trigger additional payments in excess of $140
million to Aviron.

Consideration for the license also includes a commitment to provide up to $40
million in future financing to Aviron from Wyeth-Ayerst Laboratories, a portion
of which is contingent upon regulatory approval of the product, with the
remaining amount to come from participation in future Aviron securities
offerings. The total potential value for the license fees, milestones and
financing support that Aviron could receive under the collaboration exceeds $400
million.

Wyeth will distribute the product and record all revenues. In addition to the
payments mentioned above, Aviron anticipates that it will receive in the range
of 40 percent of product revenues from Wyeth, in the form of product transfer
payments and royalties, which increase at higher sales levels. Aviron will incur
expenses to supply and co-promote the product. Further commercial terms have not
been disclosed.

Aviron is a biopharmaceutical company based in Mountain View, CA focused on
prevention of disease. The company's goal is to develop products that offer
cost-effective prevention of a wide range of infections that affect the general
population. The majority of Aviron's products under development are live
vaccines against viral infections.

FLUMIST(TM) is the company's lead vaccine candidate. Aviron plans to submit its
license application for FLUMIST(TM) to the FDA later in 1999.

The statements in this press release that are not historical facts are
forward-looking statements that involve risks and uncertainties including,
without limitation, risks associated with the inherent uncertainty of
pharmaceutical research, product development and commercialization, and the
impact of competitive products and patents. Factors relating to Aviron that
could cause actual results to differ materially include, but are not limited to
failure to receive regulatory approval for the marketing of FLUMIST(TM) or to
receive payments under collaborative agreements that are contingent upon future
events that may or may not occur. Sales of FLUMIST(TM) and future payments to
Aviron are dependent upon the successful development, manufacturing, supply,
sale 


   2
and distribution of the product by Aviron, its third party suppliers and Wyeth
Lederle. Risks and uncertainties also include those detailed from time to time
in Aviron's periodic reports filed with the Securities and Exchange Commission
including Quarterly Reports on Form 10-Q and Annual Reports on Form 10-K. Actual
results may differ from the forward-looking statements.