Beyfortus vaccine against bronchiolitis: where, at what age?

In a notice dated August 24, 2023, the General Directorate of Health indicates that the the first vaccine indicated for the prevention of bronchiolitis Beyfortus® (active substance : nirsevimab) is available in maternity hospitals and to order in pharmacies in mainland France since Friday September 15, 2023, For all infants without risk factors for severe disease experiencing their first season of exposure to RSV (respiratory syncytial virus), that is to say for this year those born from February 6, 2023. The 50 mg dosage is given as a priority to maternity wards (not in town) and the 100 mg dosage continues to be dispensed in town. for infants ≥ 5kg, can we read in a press release from the DGS on September 26, 2023. On August 1, 2023, the High Authority of Health was in favor of its reimbursement. RSV infection mainly affects children before 2 years of age. She is responsible for 80% of bronchiolitis. 2 to 3% of infants under one year of age are hospitalized for severe bronchiolitis each year. The majority of hospitalized children are infants under 6 months without risk factors.

What is the name and indications for the bronchiolitis vaccine?

The Beyfortus® vaccine developed byThe French laboratory Sanofi, in partnership with the Swedish-British group AstraZeneca, East the first vaccine authorized by the European Medicines Agency for all babies under one year old. It is indicated for the prevention of serious lower respiratory infections, due to respiratory syncytial virus (RSV), the most common cause of bronchiolitis (inflammation of the small airways in the lungs) and more rarely pneumonia (infection of the lungs). These respiratory infections are one of the leading causes of hospitalization in infants. The Synagis® vaccine (developed by AstraZeneca) already existed with another monoclonal antibody, palivizumab, but the latter is only available for premature or at-risk children.

Is the Beyfortus vaccine available in France?

Beyfortus has been approved by the European Medicines Agency and benefits froma marketing authorization (AMM) from the Committee for Medicinal Products for Human Use of theEuropean Medicines Agency since September 16, 2022. Its reimbursement was announced by the High Authority of Health on August 1, 2023. It has been available and reimbursed in maternity wards and to order in pharmacies in mainland France since Friday September 15, 2023.

What is the recommended dosage?

According to Sanofi website, the recommended dose is:

► a single dose of 50 mg administered intramuscularly for infants weighing <5 kg

► a single dose of 100 mg administered intramuscularly for infants weighing ≥5 kg.

Considering the number of doses of nirsevimab reserved and the schedule for supplying doses by the laboratory, the Directorate General of Health recommends prioritizing the use of doses of nirsevimab 50 mg in maternity. The distribution of Beyfortus dosage of 50 mg is suspended in the city for the benefit of maternity hospitals. Prescription, distribution, dispensing and immunization with Beyfortus 100mg continues in town, for infants ≥ 5kg.

What is the composition of the Beyfortus vaccine?

THE nirsevimab is the active ingredient of Beyfortus®. It is a monoclonal antibody (a type of protein).

How does the Beyfortus vaccine work?

Nirsevimab is a monoclonal antibody antiviral that was designed to bind to the F protein (fusion) which the RSV virus needs to infect the body, describes the European Medicines Agency in its press release of September 16, 2022. When nirsevimab is attached to this protein, the virus can no longer enter the body’s cells, which helps prevent RSV infection. Because the drug is eliminated from the body slowly – over several months – a single dose of Beyfortus® helps protect infants against RSV disease throughout the RSV season.

At what age can the Beyfortus vaccine be administered?

The European Medicines Agency recommends administering this vaccine (a single dose) before the RSV season (December to March in northern hemisphere countries such as France) or as soon as possible after birth for infants born during the RSV season, in other words before the age of one year. The latter is therefore indicated including in all infants without risk factors for serious form experiencing their first season of exposure to RSV, that is to say for this year those born from February 6, 2023. The recommended dose is 50 mg for children weighing less than 5 kg and 100 mg for children weighing 5 kg or more, via a single intramuscular injection which may be concomitant with infant vaccination at another injection site ( experience with concomitant administration with vaccines remains limited).

How effective is the Beyfortus vaccine against bronchiolitis?

The effectiveness and safety of the Beyfortus® vaccine have been studied in two clinical trials randomized, double-blind, placebo-controlled studies in healthy preterm and term infants entering their first RSV season. These studies demonstrated that Beyfortus® was capable of preventing lower respiratory tract infections caused by RSV requiring medical attention (such as bronchiolitis and pneumonia) in term and premature infants during their first VRS seasonwith an efficiency of between 77.3 and 79.5% (according to clinical trials).

What are the side effects of the Beyfortus vaccine?

Results from a randomized safety trial of nirsevimab showed that Beyfortus® had a similar safety profile to that of Synagis® (palivizumab). The most frequently reported adverse reactions for Beyfortus® were:

• Rashes
• Fever
• Injection site reactions, such as redness, swelling and pain at the injection site.

What is the price of the Beyfortus vaccine?

For the 2023/2024 season, Beyfortus is available without advance payment as part of the populations eligible for its administration.