Nirsevimab effective in preventing hospitalization for RSV associated lower RTI in infants

Researchers randomly assigned 12-month-old infants or younger, born at least 29 weeks gestational age and entering their first RSV season in France, Germany, or the UK, to receive a single intramuscular injection of nirsevimab or standard care before or during the RSV season.

The primary endpoint was hospitalization for RSV-associated lower respiratory tract infection. The secondary endpoint was a very severe RSV-associated lower respiratory tract infection with an oxygen saturation of less than 90% and the need for supplemental oxygen.

Key points from the study are:

• A total of 8058 infants were randomly assigned: 4037 in Nirsevimab and 4021 in the care group.
• Eleven infants and 60 infants in the nirsevimab and standard-care group were hospitalized for RSV-associated lower respiratory tract infection. This corresponded to a nirsevimab efficacy of 83.2%.
• Very severe RSV-associated lower respiratory tract infection occurred in 5 infants in the nirsevimab group, representing its efficacy as 75.7 %.
• The efficacy of nirsevimab against hospitalization for RSV-associated lower respiratory tract infections in France, Germany, and the UK was 89.6%, 74.2%, and 83.4%, respectively.
• 86 infants in the nirsevimab group experienced adverse events.

Study limitations include short study duration and trial design.

They found Nirsevimab to be protective against hospitalization for RSV-associated lower respiratory tract infections and against very severe RSV-associated lower respiratory tract infections in infants.

Sanofi and AstraZeneca funded the study.

Reference:

Simon B. Drysdale et al. Nirsevimab for Prevention of Hospitalizations Due to RSV in Infants. (n.d.). N Engl J Med 2023; 389:2425-2435