LYON, France, July 7 /PRNewswire/ --

- Novel Vaccine IMOJEV(TM) for the Prevention of Japanese Encephalitis in
Children and Adults Living in Asia

Sanofi Pasteur, the vaccines division of sanofi-aventis group, (EURONEXT: SAN
and NYSE: SNY), announced today that it has filed marketing authorization
applications in Thailand and Australia for IMOJEV(TM), its single-dose vaccine
against Japanese encephalitis (JE). This novel vaccine is aimed for the
prevention of JE in children and adults living in endemic countries in Asia.
Three billion people live in countries where JE is endemic1.

Japanese encephalitis is a viral infection that affects 30,000 to 50,000 people
each year in Asia, of which 10,000 die. JE is the most frequent and most severe
form of viral encephalitis, and is a leading cause of neurological infections in
Asia 2. There is no specific treatment for JE and the virus cannot be eradicated
given its circulation in pigs and birds.

The goal of sanofi pasteur is to provide an innovative Japanese encephalitis
vaccine to people who most need it in order to improve public health in
countries where the disease is endemic, said Wayne Pisano, chief executive
officer of sanofi pasteur. We believe IMOJEV(TM) single-dose vaccine has the
potential to transform JE vaccination in Asia and help reduce the burden of this
devastating disease.

Japanese encephalitis control through immunization is feasible and it reduces
the burden of disease, said John Wecker, Global Program Leader, Immunization
Solutions at PATH. Single-dose vaccines hold significant advantages to increase
the immunization coverage rate and simplify vaccination campaigns.

The marketing authorization files are under review by the Therapeutic Goods
Administration in Australia (TGA), and by the Food and Drug Administration in
Thailand (TFDA) which is giving the vaccine a fast track review. Clinical
studies, involving over 3,800 children and adults, evaluated the safety and
ability to generate a protective immune response with only one dose of this
novel vaccine.

The clinical data supporting the use of IMOJEV(TM) in children and in adults
have been generated in multi-center studies conducted in the United-States,
Australia, Thailand, and the Philippines with more than 2,400 adults and 1,400
children receiving IMOJEV(TM).

The safety and immunogenicity of IMOJEV(TM) was compared to a licensed Japanese
encephalitis vaccine (JE-VAX(R)) and placebo in adults and to a control vaccine
in children. A pivotal Phase III study in adults showed that a single dose of
IMOJEV(TM) is as immunogenic as three doses of JE-VAX(R). A single
administration of IMOJEV(TM) elicits a protective level of neutralizing
antibodies in 93.6% and 99% of subjects 14 days and one month after vaccine
administration, respectively. A Phase III study in children showed that 95% of
JE virus naive subjects are seroprotected one month after a single dose of
IMOJEV(TM). The vaccine is well tolerated and there was no indication during the
clinical development program of any safety concerns. The frequency of local and
systemic reactions was comparable to those reported after administration of a
placebo or a control vaccine in adult as well as in pediatric populations.

About Japanese encephalitis

Japanese encephalitis is a disease caused by a flavivirus that affects the
membranes around the brain. Most JE virus infections are mild (fever and
headache) or without apparent symptoms, but up to 1 in 200 infections results in
severe disease characterized by rapid onset of high fever, headache, neck
stiffness, disorientation, coma, seizures, spastic paralysis and death. The case
fatality rate is 30-35% among those with disease symptoms; 50% of those who
survive suffer from lasting damage to the central nervous system. In areas where
the JE virus is common, encephalitis occurs mainly in young children (1).

About sanofi-aventis

Sanofi-aventis, a leading global pharmaceutical company, discovers, develops and
distributes therapeutic solutions to improve the lives of everyone.
Sanofi-aventis is listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY).

Sanofi Pasteur, the vaccines division of sanofi-aventis Group, provided more
than 1.6 billion doses of vaccine in 2008, making it possible to immunize more
than 500 million people across the globe. A world leader in the vaccine
industry, Sanofi Pasteur offers the broadest range of vaccines protecting
against 20 infectious diseases. The company's heritage, to create vaccines that
protect life, dates back more than a century. Sanofi Pasteur is the largest
company entirely dedicated to vaccines. Every day, the company invests more than
EUR 1 million in research and development. For more information, please visit: or

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1. United Nations The United Nations urbanization prospects: the 2005 revision.
POP/DB/WUP/Rev.2005/1/F1. New York: United Nations; 2005.

2. Japanese encephalitis. WHO Initiative for Vaccine Research

SOURCE: Sanofi Pasteur

Contacts: Global Media Relations, Pascal Barollier, T: +33(0)4-37-37-50-38,; US Media Relations, Len Lavenda, T: