In The News: Nirsevimab Reduces Risk for Infants

Healio reports on research into RSV risk presented at the American College of Allergy Asthma and Immunology Annual Scientific Meeting. Researchers presented findings that infants who took the monoclonal nirsevimab had reduced risk for RSV lower respiratory tract disease. To assess, they looked into routinely administered nirsevimab at a single institution during the 2023-2024 RSV season.

The study included healthy full-term infants, excluding those who had a positive test prior to study or born those who had received a maternal RSV vaccine. Primary outcomes seen included the first PCR-confirmed RSV lower respiratory tract disease (LRTD) diagnosis and the number of medical encounters as a result of the diagnosis. PCR-confirmed RSV LRTD diagnosis was seen in 35 infants who received nirsevimab compared with 462 who did not, for an estimated treatment effectiveness of 87.2%. Only one of the 35 PCR-confirmed LTRD-diagnosed infants were hospitalized compared to 65 in the non-nirsevimab infants.

Infants in the nirsevimab group fared better overall compared to the non-nirsevimab group. Nirsevimab reduced the risk of RSV LRTD across all health care settings compared to untreated infants and that half also experienced fewer medical encounters or need for hospitalization. Total medical encounters were 75 vs. 1,241, respectively. Nearly half of healthy term infants during the season who were in that health system and eligible received the monoclonal.

The study had 15,647 infants receiving nirsevimab. Of those, 87.5% were administered in an outpatient setting. To compare, 16,253 did not receive the drug. Researchers note the demographic, racial, and ethnic characteristics of those infants were reflective of the overall Northern California population.

PIDS member Nicky Klein presented the research in the article. She commented further, “In a large study of 31,900 healthy term infants during the 2023-2024 season, of whom 49% received nirsevimab, infants who received nirsevimab had an 87% reduced risk of respiratory syncytial virus (RSV) with lower respiratory tract disease (LRTD). Receipt of nirsevimab also reduced the risk of RSV with or without LRTD by 71%. This real-world study demonstrated that nirsevimab was highly effective for the prevention of both more severe RSV LRTD as well as mild RSV in young children.”