Beyfortus™ (nirsevimab-alip) recommended for routine use to protect infants against RSV disease in CDC Morbidity and Mortality Weekly Report
The recommendation helps to ensure all infants have the opportunity to be protected from RSV disease ahead of the next winter virus season
Beyfortus is the first RSV prevention approved by the FDA to protect all infants in the U.S. through their first RSV season
Publication follows the adoption by the CDC Director of the ACIP recommendations and VFC inclusion of Beyfortus to ensure availability to a broad infant population, including for uninsured and underinsured infants at no cost to their families

BRIDGEWATER, N.J, AUGUST 24, 2023. The U.S. Centers for Disease Control and Prevention (CDC) today published the Advisory Committee on Immunization Practices (ACIP) guidance on the recommended use of Beyfortus™ (nirsevimab-alip) in the Morbidity and Mortality Weekly Report (MMWR), a journal highlighting the latest in public health news and communicating recommendations derived from science-based research.1

On August 3, the CDC’s ACIP unanimously recommended the routine use of Sanofi and AstraZeneca’s Beyfortus for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease for newborns and infants below 8 months of age born during or entering their first RSV season, and for children aged 8 to 19 months who are at increased risk of severe RSV disease and entering their second RSV season. The committee also unanimously voted to include Beyfortus in the Vaccines for Children (VFC) program, which helps to support equitable access for all eligible infants.

Michael Greenberg, MD, MPH
North America Medical Head of Vaccines, Sanofi
“For the first time, parents in the United States can enter a winter virus season knowing there is an antibody designed to protect their infants from RSV disease, the leading cause of hospitalization for babies under the age of 1. Sanofi is committed to continuing to work with stakeholders across the RSV care continuum to help ensure the seamless implementation and broad availability of this innovative prevention strategy. Our goal is to provide all babies with access to Beyfortus ahead of the upcoming 2023-2024 RSV season.”    

About MMWR
The Morbidity and Mortality Weekly Report (MMWR) is a weekly digest of epidemiological insights published by the CDC. Serving as a crucial conduit, the MMWR facilitates the distribution of CDC's public health information and recommendations, sourced from state health departments. Published material within the report resides in the public domain, enabling unrestricted reprinting without necessitating permission.

About RSV
RSV is a very contagious virus that can lead to serious respiratory illness for infants, according to the CDC. RSV symptoms can include runny nose, coughing, sneezing, fever, decrease in appetite, and wheezing.2 Two out of three infants are infected with RSV during their first year of life and almost all children are infected by their second birthday.2,3 In the U.S., RSV is the leading cause of hospitalization in infants under 12 months, averaging 16 times higher than the annual rate for influenza.4,5 Approximately 75% of infants hospitalized for RSV are born healthy and at term with no underlying conditions.6 Each year in the U.S., an estimated 590,000 RSV disease cases in infants under one require medical care, including physician office, urgent care, emergency room visits and hospitalizations.7

About Beyfortus
In the U.S., Beyfortus is the first RSV prevention approved to protect all infants through their first RSV season, including for those born healthy at term or preterm, or with specific health conditions that make them vulnerable to RSV disease. Beyfortus is also approved for children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season.

As a long-acting antibody provided directly to newborns and infants as a single dose, Beyfortus offers rapid protection to help prevent lower respiratory tract disease caused by RSV without requiring activation of the immune system.8 Beyfortus administration can be timed to the start of the RSV season.

Beyfortus was granted Breakthrough Therapy and Fast-Track designations and was approved by the FDA on July 17, 2023 following the positive recommendation of the U.S. Food and Drug Administration Antimicrobial Drugs Advisory Committee. The approval was based on the extensive Beyfortus clinical development program spanning three pivotal late-stage clinical trials. Across all clinical endpoints, a single dose of Beyfortus delivered high, consistent and sustained efficacy against RSV lower respiratory tract disease extending through five months, a typical RSV season.

In March 2017, Sanofi and AstraZeneca announced an agreement to develop and commercialize Beyfortus. Under the terms of the agreement, AstraZeneca leads development and manufacturing activities and Sanofi leads commercialization activities and records revenues. Under the terms of the global agreement, Sanofi made an upfront payment of €120m, has paid development and regulatory milestones of €120m and will pay up to a further €375m upon achievement of certain regulatory and sales-related milestones. The two companies share costs and profits in all territories except in the U.S. where Sanofi consolidates 100% of the economic benefits in its Business Operating Income.

Beyfortus is a prescription medicine used to help prevent a serious lung disease caused by Respiratory Syncytial Virus (RSV) in:

  • newborns and babies under 1 year of age born during or entering their first RSV season.
  • children up to 24 months of age who remain at risk of severe RSV disease through their second RSV season.

Your child should not take Beyfortus if your child has a history of serious allergic reactions to nirsevimab-alip or any of the ingredients in Beyfortus.

Before your child receives Beyfortus, tell your healthcare provider about all of your child’s medical conditions, including if your child:

  • has ever had a reaction to Beyfortus.
  • has bleeding or bruising problems. If your child has a problem with bleeding or bruises easily, an injection could cause a problem.

Tell your healthcare provider about all the medicines your child takes, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Your infant should not receive a medicine called palivizumab if they have already received Beyfortus in the same RSV season.

Serious allergic reactions have happened with other medicines like Beyfortus. Get medical help right away if your child has any of the following signs or symptoms of a serious allergic reaction:

  • swelling of the face, mouth, or tongue
  • difficulty swallowing or breathing
  • unresponsiveness
  • bluish color of skin, lips, or under fingernails
  • muscle weakness
  • severe rash, hives, or itching

The most common side effects of Beyfortus include rash and pain, swelling, or hardness at the site of your child’s injection. These are not all the possible side effects of Beyfortus. Call your healthcare provider if you have questions about side effects.

Please see full Prescribing Information, including Patient Information for more details.

About Sanofi
We are an innovative global healthcare company, driven by one purpose: we chase the miracles of science to improve people’s lives. Our team, across some 100 countries, is dedicated to transforming the practice of medicine by working to turn the impossible into the possible. We provide potentially life-changing treatment options and life-saving vaccine protection to millions of people globally, while putting sustainability and social responsibility at the center of our ambitions.

Sanofi is listed on EURONEXT: SAN and NASDAQ: SNY

Media Relations
Evan Berland | +1 215 432 0234 |

Investor Relations
Eva Schaefer-Jansen | + 33 7 86 80 56 39 |
Arnaud Delépine | + 33 6 73 69 36 93 |
Corentine Driancourt | + 33 6 40 56 92 21 |  
Felix Lauscher | + 1 908 612 7239 |
Tarik Elgoutni| + 1 617 710 3587 |
Nathalie Pham | + 33 7 85 93 30 17 |

Sanofi Forward-Looking Statements
This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements are statements that are not historical facts. These statements include projections and estimates and their underlying assumptions, statements regarding plans, objectives, intentions and expectations with respect to future financial results, events, operations, services, product development and potential, and statements regarding future performance. Forward-looking statements are generally identified by the words “expects”, “anticipates”, “believes”, “intends”, “estimates”, “plans” and similar expressions. Although Sanofi’s 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, 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 among other things, the uncertainties inherent in research and development, future clinical data and analysis, including post marketing, decisions by regulatory authorities, such as the FDA or the EMA, regarding whether and when to approve any drug, device or biological application that may be filed for any such product candidates as well as their decisions regarding labelling and other matters that could affect the availability or commercial potential of such product candidates, the fact that product candidates if approved may not be commercially successful, the future approval and commercial success of therapeutic alternatives, Sanofi’s ability to benefit from external growth opportunities, to complete related transactions and/or obtain regulatory clearances, risks associated with intellectual property and any related pending or future litigation and the ultimate outcome of such litigation,  trends in exchange rates and prevailing interest rates, volatile economic and market conditions, cost containment initiatives and subsequent changes thereto, and the impact that pandemics or other global crises may have on us, our customers, suppliers, vendors, and other business partners, and the financial condition of any one of them, as well as on our employees and on the global economy as a whole. The risks and uncertainties also include the uncertainties discussed or identified in the public filings with the SEC and the AMF made by Sanofi, including those listed under “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Statements” in Sanofi’s annual report on Form 20-F for the year ended December 31, 2022. Other than as required by applicable law, Sanofi does not undertake any obligation to update or revise any forward-looking information or statements.


  1. Jones JM, Fleming-Dutra KE, Prill MM, et al. Use of Nirsevimab for the Prevention of Respiratory Syncytial Virus Disease Among Infants and Young Children: Recommendations of the Advisory Committee on Immunization Practices — United States, 2023. MMWR Morb Mortal Wkly Rep 2023;72:920–925. DOI:
  2. CDC. RSV in Infants and Young Children. Accessed August 2023.
  3. Glezen WP, Taber LH, Frank AL, Kasel JA. Risk of primary infection and reinfection with respiratory syncytial virus. Am J Dis Child. 1986;140(6):543-546. doi:10.1001/archpedi.1986.02140200053026
  4. Suh M, et al. J Infect Dis. 2022 Aug 15;226(Suppl 2):S154-S163. doi: 10.1093/infdis/jiac120. PMID: 35968878; PMCID: PMC9377046.
  5. Zhou H, et al. Clin Infect Dis. 2012;54:1427–1436.
  6. Arriola CS, Kim L, Langley G, et al. Estimated burden of community-onset respiratory virus–associated hospitalizations among children aged <2 years in the United States, 2014-15. J Pediatric Infect Dis Soc. 2020;9(5):587-595.
  7. Rainisch G, et al. Estimating the impact of multiple immunization products on medically-attended respiratory syncytial virus (RSV) infections in infants. Vaccine. 2020;38(2):251-257.
  8. Centers for Disease Control and Prevention. Vaccines & Immunizations. August 18, 2017. Accessed August 2023.