The European Medicines Agency has recommended the antibody nirsevimab for a marketing authorization in the European Union. This means that, when the European Commission accepts this recommendation, the antibody can be used in the EU for the prevention of Respiratory Syncytial Virus (RSV) infections in newborn babies and infants. It is expected that the antibody will be available in the EU in 2023.


Respiratory syncytial virus (RSV) is a common cause of childhood infections. In most cases, an infection only leads to mild, cold-like symptoms, but RSV can also give rise to lower respiratory infection such as bronchiolitis. The virus is a major cause of hospital admissions in young children. In 2015, it was estimated that globally, there were 33.1 million cases of RSV which led to around 3.2 million hospital admissions and 59,600 in-hospital deaths in children younger than 5 years.

Monoclonal antibody

Nirsevimab is designed for all infants for protection against RSV disease from birth through their first RSV season with a single dose. The antibody, that will be marketed under the name Beyfortus®, has been developed to offer newborns and infants direct RSV protection to help prevent lower respiratory tract infections caused by RSV. Monoclonal antibodies such as nirsevimab do not require the activation of the immune system to help offer timely, rapid and direct protection against disease.

Amsterdam UMC

The antibody, that will be marketed under the name Beyfortus®, is being developed jointly by Sanofi and AstraZeneca and is based on research from Amsterdam UMC, location AMC. Antibodies are normally produced by B-cells, white blood cells that are part of the body’s immune system. B-cells recognize viruses and other pathogens entering the body and respond with the production of antibodies that help neutralize such pathogens.

In 2007, Hergen Spits and his Amsterdam UMC research discovered a method to make these B-cells immortal and to grow them perpetually in the lab. This technology was used by the AMC Ventures participation AIMM to develop an antibody to protect against the RS virus. They found DNA that encodes an RSV-specific antibody in the B-cells of patients who recovered from RSV infections. With the use of this DNA, the immortalized B-cells were turned into RSV antibody-producing cells. The rights to the clinical development of this antibody were licensed out to AstraZeneca in 2009. When AIMM shifted their focus to the development of antibodies for cancer therapies, this license was transferred to a new AMC Ventures participation, R-South, named after the R-South building next to the AMC main building, where most of the research and development activities had taken place.