SANOFI PASTEUR SIGNS CONTRACT WITH FRENCH GOVERNMENT TO PRODUCE PANDEMIC INFLUENZA VACCINE

Alain BERNAL Vice-President Corporate Communications Tel: + 33-(0)4-37-37-78-97 Fax: +33-(0)4-37-37-77 89 Len LAVENDA U.S. Media Relations Tel: +1-570-839-4446 Len.Lavenda@sanofipasteur.com ~ Influenza Vaccine Leader sanofi Pasteur Contributes to French Pandemic Preparedness ~ Lyon, France – November 10, 2005 – Following discussions which started a few months ago, sanofi pasteur, the vaccines business of the sanofi-aventis Group, has entered into an agreement with the French Ministry of Health to produce pre-pandemic vaccine in 2005 against the H5N1 influenza virus strain, the so-called avian strain. This will create a stockpile of 1,400,000 doses of vaccine. Scientists believe the H5N1 strain could become the cause of a global influenza pandemic. The agreement also commits the company to being ready to provide enough vaccine for 28 million people in the event of a pandemic being declared, once the actual virus strain responsible has been identified. According to the terms of the contract, in 2005, sanofi pasteur is to supply in bulk concentrate form the H5N1 vaccine produced in its Val de Reuil, France, facility. Formulation and filling of the vaccine can then be carried out, at any time, at the request of the French authorities. Trials with H5N1 vaccine have been launched at three sites in France using the clinical lots produced by sanofi pasteur during 2005. The aim of the trials was to evaluate the safety and immunogenicity of the vaccine and to determine its optimal formulation, especially concerning the adjuvant. The results should be known by the end of 2005. They will be used in the preparation of a “mock-up” registration file for submission to the European Medicines Agency (EMEA) so that registration of the actual pandemic vaccine can be speeded up in case of pandemia. The sanofi pasteur contract with the French government, which will be carried out in collaboration with sanofi pasteur MSD, is another major step by the company in its support of efforts to prepare the world for the possibility of an influenza pandemic. Sanofi pasteur is investing in a major expansion of its influenza vaccine production capacity in the USA, and also of its vaccine production capacity in France (Val de Reuil facility). The company is also involved in a number of other initiatives: • Sanofi pasteur has entered into a series of contracts with the US government to increase that country’s pandemic preparedness efforts. The contracts include investigational doses for clinical trials; bulk vaccine for stockpiles; establishment and maintenance of laying flocks to enable year-round egg production (not just seasonal), as well as a contract to speed the production process for new cell culture influenza vaccines, including the design of a US-based cell-culture vaccine manufacturing facility. • A contract has also been signed with the Australian government for the supply of vaccine in the event of a pandemic influenza outbreak. There are also contracts concerning pandemic preparedness between sanofi pasteur and many other governments in Europe and worldwide, as well as with the international organizations. Some of these contracts might lead to further contracts for collaboration and vaccine supply. • In addition, sanofi pasteur is the only vaccine manufacturer to participate in FLUPAN, an EU-funded collaboration. FLUPAN partners include the National Institute for Biological Standards & Control (NIBSC - UK), the University of Reading (UK), Istituto Superiore di Sanita, (Italy), the Health Protection Agency (UK), and the University of Bergen (Norway). FLUPAN is intended to improve the level of pandemic preparedness in the EU. Sanofi pasteur is to produce a vaccine to combat another strain with pandemic potential (H7N1) that will be used in a FLUPAN clinical study. The experience accumulated in this way with pilot strains H5N1 and H7N1 may prove to be crucial if it becomes necessary to develop and produce at full speed and full scale a vaccine against the strain which is eventually identified as responsible for the pandemic. Influenza Overview Influenza is a highly contagious virus that is spread easily from person to person, primarily when an infected individual coughs or sneezes. An influenza pandemic is a global epidemic of an especially virulent virus with the potential for severe morbidity and mortality. According to the World Health Organization (WHO), the next pandemic is likely to result in 1 to 2.3 million hospitalizations and 280,000 to 650,000 deaths in industrialized nations alone. Its impact will most likely be even more devastating in developing countries. About sanofi-aventis The sanofi-aventis Group is the world’s third-largest pharmaceutical company, ranking number one in Europe. Backed by a world-class R&D organization, sanofi-aventis is developing leading positions in seven major therapeutic areas: cardiovascular disease, thrombosis, oncology, metabolic diseases, central nervous system, internal medicine, and vaccines. The sanofi-aventis Group is listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY). Sanofi pasteur, the vaccines business of the sanofi-aventis Group, sold nearly a billion doses of vaccine in 2004, making it possible to protect more than 500 million people across the globe, which is about 1.4 million per day. The company offers the broadest range of vaccines, providing protection against 20 bacterial and viral diseases. For more information, please visit: www.sanofipasteur.com Forward Looking Statements This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995. Forward-looking statements are statements that are not historical facts. These statements include financial projections and estimates and their underlying assumptions, statements regarding plans, objectives and expectations with respect to future operations, products and services, and statements regarding future performance. Forward-looking statements are generally identified by the words “expect,” “anticipates,” “believes,” “intends,” “estimates,” “plans” and similar expressions. Although sanofi-aventis’ management believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of sanofi-aventis, that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks and uncertainties include those discussed or identified in the public filings with the SEC and the AMF made by sanofi-aventis, including those listed under “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Statements” in sanofi-aventis’ annual report on Form 20-F for the year ended December 31, 2004. Other than as required by applicable law, sanofi-aventis does not undertake any obligation to update or revise any forward-looking information or statements. Sanofi-aventis Group subsidiaries in the United States include Sanofi-Synthelabo Inc., Aventis Pharmaceuticals Inc. and Sanofi Pasteur Inc.