According to one trial, hospitalizations for bronchiolitis can be cut in half with a single dose of nirsevimab, a long-acting antibody designed to prevent respiratory syncytial virus infections in newborns.

Children under one year old are primarily affected by bronchiolitis, an acute viral infection that primarily affects the respiratory system during the first six months of life and is more common between November and March.

In almost three out of four cases, it is linked to a respiratory syncytial virus infection, which can lead to respiratory failure, particularly in infants younger than a year old.

First, by contrasting European nations with disparate health policies—Spain, the UK, and Italy—the real-world study examined the tangible effects of nirsevimab.

Hospitalizations for bronchiolitis in children under six months in Catalonia have nearly halved in comparison to the average of prior seasons, according to data gathered from 68 Catalan hospitals in Spain and five hospitals in the UK and Italy.

Significantly fewer people in the same age range were admitted to the emergency room. However, in the other European centers where nirsevimab was not used, no discernible decrease was found.

According to Danilo Buonsenso, a researcher in General and Specialist Paediatrics at the Catholic University in the United States, the study, which was published in the journal Lancet Regional Health – Europe, “represents an important step in assessing the real effectiveness of new preventive strategies against RSV, comparing for the first time countries with different approaches to its implementation.”

The study also revealed that the effect of nirsevimab was less noticeable in older children (those aged six to 23 months), indicating that the first few months of life are when it is most effective.

In order to prevent infants from respiratory syncytial virus (RSV), the primary cause of acute lower respiratory infections in children worldwide, the World Health Organization (WHO) advised all nations to use nirsevimab in conjunction with a maternal vaccine called RSVpreF in May.

Nirsevimab is administered as a single injection of monoclonal antibodies that begins to protect infants against RSV within a week of administration, however the vaccine can be administered during standard prenatal care. In nations where RSV seasonality exists, it can last for the full RSV season and lasts for at least five months.

The world health organization advises giving newborns a single dosage of nirsevimab either immediately after birth or before to their release from a hospital.