Effective Use of Monoclonal Antibody Nirsevimab in Protecting Infants from Severe RSV Infection: Insights from a Meta-Analysis

A recent meta-analysis published in The Lancet Child & Adolescent Health highlights the significant real-world effectiveness of nirsevimab, a monoclonal antibody, in preventing severe respiratory syncytial virus (RSV) infections in infants. RSV remains a major cause of serious respiratory illness among young children, especially in their first six months, leading to millions of hospitalizations worldwide annually.

Following successful clinical trials, regulatory agencies authorized nirsevimab in 2023, and several high-income countries have incorporated it into their infant immunization programs. Unlike vaccines, which stimulate the body's immune response, nirsevimab is a lab-made protein that directly provides passive immunity by mimicking the immune system.

The meta-analysis examined data from 27 studies conducted during the 2023–2024 RSV season across France, Italy, Luxembourg, Spain, and the United States. The findings demonstrate that nirsevimab significantly reduces the risk of hospitalization due to RSV by 83%, admissions to intensive care units by 81%, and cases of lower respiratory tract infections by 75% in children under 12 months.

Notably, the antibody showed higher effectiveness in preventing RSV-related hospitalizations in infants older than three months (81%) compared to those three months or younger (76%). Effectiveness varied by country, with the US experiencing the highest reduction (93%), likely due to prioritization of high-risk infants amid limited supplies—though further research is needed to confirm this hypothesis.

The authors underscore that these findings support nirsevimab as a vital intervention against RSV in infants. However, they also acknowledge limitations, including the observational nature of the included studies, which may introduce biases stemming from factors like health conditions, socioeconomic status, or regional healthcare access disparities.

Overall, this evidence confirms that deploying nirsevimab in national programs can substantially decrease severe RSV outcomes, offering hope for improved infant health worldwide.

Source: Medical Xpress