Bronchiolitis: European Medicines Agency approves new preventive treatment

The European Medicines Agency (EMA) recommended this Friday, September 19, the marketing of a treatment against the virus responsible for bronchiolitis , developed by the American laboratory MSD .

"The committee recommended granting marketing authorization for Enflonsia (clesrovimab)," the European regulator said in a statement.

This is a treatment indicated for the prevention of respiratory syncytial virus (RSV) "in newborns and infants," the agency said.

Enflonsia will compete with Beyfortus (nirsevimab) , an injectable synthetic antibody marketed by Sanofi for the immunization of infants against bronchiolitis, whose vaccination campaign began at the beginning of the month in France.

Enflonsia is a long-acting preventative monoclonal antibody "designed to provide direct, rapid, and long-lasting protection for 5 months, a typical RSV season," says the website of the American pharmaceutical company MSD (Merck Sharp & Dohme).

The treatment was approved in the United States and the United Arab Emirates in June 2025.

RSV is a common, seasonal virus that causes lower respiratory tract infections. Its symptoms are similar to those of a cold, "but can also affect the lungs," explains the EMA.

Nearly all children contract RSV infection before the age of two, the agency said. "While most recover quickly, in some children, RSV can cause severe illness that can lead to hospitalization or even death," the statement said.

A final decision from the European Commission is expected by the end of the year, MSD said on its website.