The respiratory syncytial virus vaccine also appears to protect against asthma

Protecting newborns from the Respiratory Syncytial Virus (RSV) would have the dual effect of protecting them from an infection with potentially serious implications and reducing the risk of the little ones becoming ill with asthma. An important study conducted in Denmark has in fact discovered that children infected with RSV in early childhood are more likely to develop asthma later, especially if there have been or are other cases of asthma or allergies in the family. The research results were published on Science Immunology.

The Respiratory Syncytial Virus (RSV) is a virus that infects the respiratory system and which in most cases gives “classic” symptoms such as coughs and colds, but which in some circumstances can cause more complex situations, such as bronchiolitis, the partial closure of the small bronchi. This type of complication can cause respiratory failure and most frequently affects infants and children under the age of two.

Fortunately, we can protect ourselves from the syncytial virus, responsible for 15-20 percent of all hospitalizations in children under 2 years of age. A vaccine has been available since 2023 – Abrysvo, approved by EMA and AIFA – to protect people over 60 and pregnant women. Maternal vaccination, to be carried out between the 24th and 36th week of pregnancy, protects newborns up to 6 months of age.

Furthermore, in the 2024-2025 winter season, protection was introduced with a long-acting monoclonal antibody, Nirsevimab, which binds to the syncytial virus and prevents its replication. This protection is available to all newborns and is administered only once at the beginning of the cold season, the period with greatest risk. Since it is not a vaccine, the monoclonal antibody does not prevent infection, but limits the most serious outcomes. This is why pediatric health experts consider it a revolutionary contribution.

By analyzing the health databases of all Danish children and through laboratory investigations, a group of scientists from the Vlaams Instituut voor Biotechnologie and Ghent University (Belgium), with the collaboration of Danish scientists and as part of a European Research Council project, discovered that an early syncytial virus infection and a family history of allergies or asthma are factors that amplify each other.

In particular, newborns who experience a severe form of RSV infection in the first months of life show an increased probability of an excessive reaction of immune cells to common allergens (such as house dust mites).

The effect is even more evident and intensified if children have a family history of asthma or allergies, because specific antibodies for certain allergens can be transmitted from parents to children and this inheritance can make them more sensitive to asthma triggers.

The authors of the study also found that when children are protected from the syncytial virus, because their mothers were vaccinated during pregnancy or because they receive long-lasting protection before the winter season with long-acting antibodies, this amplifying effect does not occur and the children are also more protected from asthma. Let us remember that asthma is one of the most common chronic diseases of childhood: it affects 5-15 percent of children in Europe (in Italy it affects around 260,000 children), and is aggravated by environmental factors such as pollution and global warming.

The accessibility of syncytial virus prevention could offer an unprecedented opportunity to reduce the risk of a debilitating chronic respiratory disease and improve long-term pediatric respiratory health: “This is not just a laboratory discovery” explains Hamida Hammad, senior author of the study. “It is a message that should help parents choose RSV prevention with confidence.”