This authorization of the Arexvy vaccine, developed by the British pharmaceutical giant GSK, was granted by the US Drug Administration (FDA) for adults 60 years of age and older.

This represents "an important public health success in preventing a disease that can be fatal," said Peter Marks, head of the FDA.

Last week, the same vaccine received a positive opinion from the European Medicines Agency (EMA). The final decision of the European Commission is expected in the coming months.

RSV is a widespread and highly contagious virus, best known for causing bronchiolitis (infection of the small bronchi) in toddlers during the winter. But it also affects adults and can be dangerous for the elderly when it degenerates into a respiratory infection (bronchiolitis or pneumonia).

After decades of research, a race is underway between several pharmaceutical groups to win this market that promises to be juicy.

Pfizer and Moderna are also each developing an RSV vaccine for the elderly. Pfizer said it expects a decision from the U.S. FDA on its approval in May.

According to US health authorities, this virus causes the death of between 6,000 and 10,000 people aged 65 and over in the United States each year, and between 60,000 and 160,000 hospitalizations.

GSK said in a statement that its vaccine would be available as early as the next epidemic season this year.

Large clinical trial

GSK's vaccine approval is based on a clinical trial with about 25,000 participants, half of whom received the vaccine and the other half a placebo. The vaccine was 83% effective in preventing lower respiratory tract infections.

Side effects were mainly fatigue, muscle pain, or headache.

In another, smaller study, one participant developed Guillain-Barré syndrome, a rare neurological disease, nine days after receiving the Arexvy vaccine. The FDA has asked GSK to continue conducting studies to monitor this risk.

Every winter, bronchiolitis is in the spotlight, but it was particularly talked about last year, in a context of the end of confinements related to Covid-19, and therefore increased circulation of viruses.

The United States and Europe have been particularly hard hit, especially babies, who had avoided exposure during the Covid pandemic.

At the end of 2022, the European Union approved a preventive treatment for bronchiolitis developed jointly by AstraZeneca and Sanofi. Intended for infants, nirsevimab is not strictly speaking a vaccine but works with the same preventive intention.

© 2023 AFP