Prevention of severe RSV disease in babies

RSV or RS virus (respiratory syncytial virus) is a common cause of respiratory tract infection in people of all ages. The number of cases tends to increase in late fall and in the winter. The infection spreads easily through, for example, hand contact and sneezing. Almost all children get a respiratory tract infection caused by RSV during early childhood. Most only experience mild cold-like symptoms.  

RSV is a common cause of hospitalization in babies. In children under twelve months of age (and especially children under three months of age), the virus can cause a lower respiratory tract infection with symptoms such as cough, increased mucus/phlegm production, loss of appetite, fatigue, rapid and superficial breathing, and pauses in breathing. Symptoms can get worse quickly and require urgent hospitalization or even intensive care. 

Nirsevimab is effective in preventing severe RSV infections. The medicine starts to work almost immediately, and its effect lasts for one RSV season. The antibody is at its most useful when given at the start of the RSV season. Nirsevimab is administered as a single intramuscular injection. It is not a vaccine. Nirsevimab can be given at the same time as vaccines from the vaccination program. If the mother was vaccinated against RSV during pregnancy at least 2 weeks before giving birth, the baby will not need nirsevimab.  

Nirsevimab has been shown to be very safe in clinical studies. The medicine does not contain RSV and cannot cause an RSV infection. Adverse effects are relatively rare. Potential adverse effects include rash, fever, and redness, swelling, or pain at the injection site.