New medicine to protect babies and infants from respiratory syncytial virus (RSV) infection

News 16/09/2022

EMA has recommended a marketing authorisation in the European Union (EU) for Beyfortus (nirsevimab) for the prevention of Respiratory Syncytial Virus (RSV) lower respiratory tract disease in newborn babies and infants during their first RSV season (when there is a risk of RSV infection in the community).

RSV is a common respiratory virus that usually causes mild, cold-like symptoms. Most people recover within one to two weeks, but RSV can be serious, especially in infants. It is the most common cause of lower respiratory tract infections, such as bronchiolitis (inflammation of the small airways in the lungs) and pneumonia (infection of the lungs) that may lead to hospitalisation or even death in newborn babies and young infants. For instance in 2015, RSV caused an estimated 33 million lower respiratory tract infections in children younger than five years globally; 3.2 million of them required hospitalisation. Approximately 59,600 children died, the vast majority (43,600) in low- and middle-income countries. Despite a decrease in the number of RSV infections during the pandemic in 2020 and 2021, a resurgence in infections is expected following the easing of COVID-19 mitigation measures. In the EU, the virus is usually more common during the winter.  

Nirsevimab, the active substance in Beyfortus, is an antiviral monoclonal antibody (a type of protein), which has been designed to attach to the F (fusion) protein that RSV needs to infect the body. When nirsevimab is attached to this protein, the virus becomes unable to enter the body’s cells. This helps to prevent RSV infection. Because the medicine is removed slowly from the body, over a period of several months, a single dose of Beyfortus protects infants against RSV disease during the entire RSV season.

Beyfortus was supported through EMA's PRIority MEdicines (PRIME) scheme, which provides early and enhanced scientific and regulatory support to promising new medicines that address unmet medical needs. Beyfortus was also evaluated under EMA's accelerated assessment mechanism because prevention of RSV infection in all infants is considered to be of major public health interest.

The opinion by EMA’s committee for human medicines (CHMP) is based on data from two randomised, double-blind, placebo-controlled multicentre clinical trials that investigated the efficacy and safety of nirsevimab in healthy preterm (premature) and full-term infants entering their first RSV season. These studies demonstrated that Beyfortus prevents lower respiratory tract infection caused by RSV requiring medical attention (such as bronchiolitis and pneumonia) in term and preterm infants during their first RSV season.

The safety of nirsevimab was also evaluated in a phase II/III, randomised, double‑blind, multicentre trial in infants who were born five or more weeks prematurely (less than 35 weeks gestation) at higher risk for severe RSV disease and infants with chronic lung disease of prematurity (i.e. long-term respiratory problems faced by babies born prematurely) or congenital heart disease. The results of this study showed that Beyfortus had a similar safety profile compared to Synagis (palivizumab). The most common side effects reported for Beyfortus were rash, pyrexia (fever) and injection site reactions (such as redness, swelling and pain where the injection is given).

The opinion adopted by the CHMP is an intermediary step on Beyfortus’ path to patient access. The opinion will now be sent to the European Commission for the adoption of a decision on an EU-wide marketing authorisation. Once a marketing authorisation has been granted, decisions about price and reimbursement will take place at the level of each Member State, taking into account the potential role/use of this medicine in the context of the national health system of that country.


  • Beyfortus should be given before the RSV season (when there is a risk of RSV infection in the community) or as soon as possible after birth for infants born during the RSV season. In the northern hemisphere, this is from December to March.
  • The applicant for Beyfortus is AstraZeneca AB.
  • Beyfortus was accepted into the PRIME scheme on 31 January 2019.

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