Meta-Analysis Highlights Efficacy of Monoclonal Antibody Against Severe RSV in Infants

Recent findings published in The Lancet Child & Adolescent Health underscore the effectiveness of nirsevimab, a monoclonal antibody, in providing substantial protection against severe respiratory syncytial virus (RSV) infections among infants. This meta-analysis, which encompasses data from 27 studies conducted during the 2023-2024 RSV season across five countries, indicates that nirsevimab significantly reduces the risk of severe outcomes associated with RSV.

RSV is recognized as a prominent cause of severe respiratory illness in young children, particularly during the first six months of life, leading to millions of hospitalizations worldwide each year. Following successful clinical trials, nirsevimab received approval from various regulatory agencies in 2023, and subsequent national programs have been initiated in several high-income nations to administer this monoclonal antibody to infants.

The analysis reveals that nirsevimab lowers the risk of hospitalization due to RSV by an average of 83%, intensive care admissions by 81%, and occurrences of lower respiratory tract infections by 75% in infants aged 12 months or younger. Notably, the effectiveness of nirsevimab was found to be greater in infants older than three months (81%) compared to those under three months (76%).

Furthermore, the study highlights variations in the effectiveness of nirsevimab across different countries, with the United States reporting a 93% effectiveness rate in preventing RSV-related hospitalizations, in contrast to 83% in Spain and 76% in France. This discrepancy may be attributed to a higher proportion of high-risk infants receiving nirsevimab in the U.S. during the 2023-2024 RSV season, although more research is needed to substantiate this theory.

While the findings strengthen the case for nirsevimab as a crucial intervention in preventing severe RSV disease among infants, researchers caution that the studies included in the meta-analysis were observational in nature. This may introduce potential biases due to factors such as underlying health conditions, socioeconomic status, and regional variations in healthcare access.

In conclusion, the study supports the integration of nirsevimab into national health strategies aimed at reducing the burden of RSV in infants, emphasizing its role in preventing severe respiratory illnesses.