A new study released today in the April issue of The Pediatric Infectious Disease Journal about the transmission of pertussis -- commonly known as whooping cough -- found that household members were the source for 71 to 82 percent of cases among infants for whom a source case could be identified.(1) The study demonstrates the importance of vaccination of close contacts of infants to reduce the number of infant pertussis cases and potentially save lives.(1,2)

The study, the first simultaneous evaluation of infant pertussis conducted in four countries [including the United States], was led by researchers at the University of North Carolina, Chapel Hill (UNC-CH) and was supported by sanofi pasteur, the vaccines business of the sanofi-aventis Group. This study was conducted over a 20-month period and found that, among infants with pertussis for whom the source could be identified, parents were the source of 55 percent of cases, followed by siblings (16 percent), aunts/uncles (10 percent), friends/cousins (10 percent), grandparents (6 percent), and part-time caregivers (2 percent).(1) In previous studies, identifying the source of infection was hindered by incomplete case data and less comprehensive laboratory evaluation of contacts.

Pertussis is a highly contagious bacterial infection. The disease is spread though airborne droplets that are transmitted when an infected person coughs or sneezes. It may start with symptoms similar to a mild cold or a dry cough that persists and eventually worsens. The infected person may look and feel healthy between episodes of coughing. If left untreated, pertussis can be spread for several weeks. At particular risk are newborns who have not been vaccinated or fully vaccinated against the disease.(3) They are more vulnerable to severe pertussis and face the possibility of serious complications and even death. In fact, more than 90 percent of pertussis deaths have occurred in infants.(4)

"While pertussis cases in all age groups have been rising, it is important to know how the disease is spread, particularly to infants who are too young to be vaccinated themselves, so that steps can be taken to prevent infections in these vulnerable infants and potentially save lives," said Annelies Van Rie, M.D., assistant professor of epidemiology in the UNC School of Public Health. "It is troubling to learn that infants are often infected with pertussis by their own family members, who are often unaware of having pertussis themselves."

The number of reported cases of pertussis has been rising across the United States, heightening concern in the public health and medical communities. This is partly because pertussis immunity from early childhood vaccinations eventually wears off, leaving adults and adolescents susceptible to the disease. The most current data from the United States Centers for Disease Control and Prevention (CDC) indicate that the number of pertussis cases increased between the 1980s and 2005.(4) While the number of cases increased in all age groups, reports of pertussis have increased most dramatically among adolescents and adults. Most adolescents and adults are not diagnosed with pertussis because they frequently have milder disease.

The Advisory Committee on Immunization Practices (ACIP) of the CDC now recommends that adults and adolescents be given a tetanus-diphtheria-pertussis booster (Tdap) in place of the tetanus-diphtheria (Td) booster to reduce the burden of pertussis in this country.(5) Since 2005, Adacel vaccine has offered pertussis protection for individuals 11 through 64 years of age, and is currently the only pertussis booster vaccine for both adolescents and adults in the United States.

"Ongoing research, such as this study, demonstrates that adolescents and adults can transmit pertussis to infants and that pertussis immunization of adolescents and adults would not only have an effect on their own health, but would also protect young infants from pertussis," said Dr. Van Rie. "Those who have an infant at home or who come into contact with infants at work should be immunized against pertussis."

About Adacel Vaccine

Adacel vaccine is the first booster to address pertussis protection across a wide range of ages (11 through 64 years) and the first and only booster licensed for adults in the United States. It was licensed by the U.S. Food and Drug Administration (FDA) on June 10, 2005. Adacel vaccine is administered as a single, 0.5mL dose by intramuscular injection. It is similar to DAPTACEL(R) (Diphtheria and Tetanus Toxoids and Acellular Pertussis Vaccine Adsorbed), a diphtheria, tetanus, and pertussis vaccine used to protect infants and young children because it is also based on sanofi pasteur's 5-antigen pertussis vaccine. In clinical studies, DAPTACEL vaccine has been shown to provide 85 percent efficacy against severe pertussis (cough lasting 21 days or longer) and 78 percent efficacy against all severities of pertussis.

Important Safety Information

There are risks associated with all vaccines. The most common injection site adverse events include pain, erythema, and swelling. The most common systemic adverse events include headache, body ache, tiredness, and fever. Adacel vaccine is contraindicated in persons with known systemic hypersensitivity to any component of the vaccine or a life-threatening reaction after previous administration of the vaccine or a vaccine containing the same substances. Because of uncertainty as to which component of the vaccine may be responsible, no further vaccination with the diphtheria, tetanus, or pertussis components found in Adacel vaccine should be carried out. Because any intramuscular injection can cause injection site hematoma, Adacel vaccine should not be given to persons with any bleeding disorder, such as hemophilia or thrombocytopenia, or to persons on anticoagulant therapy unless the potential benefits clearly outweigh the risk of administration. If the decision is made to administer Adacel vaccine to such persons, it should be given with caution, with steps taken to avoid the risk of hematoma formation following injection.

For full prescribing information, see the Adacel vaccine package insert at http://www.adacelvaccine.com. For information on where to get an Adacel vaccine, visit http://www.adacel-locator.com.

About sanofi-aventis

Sanofi-aventis is one of the world leaders in the pharmaceutical industry, 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, thrombosis, oncology, metabolic diseases, central nervous system, internal medicine and vaccines. Sanofi-aventis is listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY).

Sanofi pasteur, the vaccines business of the sanofi-aventis Group, sold more than a billion doses of vaccine in 2005, making it possible to protect more than 500 million people across the globe. The company offers the broadest range of vaccines, providing protection against 20 bacterial and viral diseases. For more information, please visit: http://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 events, 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, 2005. Other than as required by applicable law, sanofi-aventis does not undertake any obligation to update or revise any forward-looking information or statements.

References

1) Van Rei A. Transmission of Bordetella pertussis to young infants. Pediatr Infect Dis J. April 2007.

(2) Vitek CR, Pascual FB, Baughman AL, Murphy TV. Increase in deaths from pertussis among young infants in the United States in the 1990's. Pediatr Infect Dis J. 2003;22:628-34.

(3) CDC. Outbreaks of Pertussis Associated with Hospitals - Kentucky, Pennsylvania, and Oregon, 2003. MMWR. 2004;54(3):67-71.

(4) Centers for Disease Control and Prevention (CDC). Division of Bacterial and Mycotic Diseases. Pertussis Disease Information. Available at: http://www.cdc.gov/ncidod/dbmd/diseaseinfo/pertussis_t.htm. Accessed February 9, 2007.

(5) CDC. Preventing Tetanus, Diphtheria, and Pertussis Among Adults: Use of Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccine. MMWR 2006;55(No. RR-17):1-37 Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5517a1.htm. Accessed February 12, 2007.

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