Study finds lab-created antibody effective in preventing severe respiratory illness in infants

The Hindu

04-05-2025

A monoclonal antibody -- a protein created in a lab which mimics the work of a natural antibody -- could be highly effective in preventing severe RSV-- Respiratory syncytial virus, a respiratory infection and major cause of serious illness in infants, according to a research.
Study findings
Findings of the study, published in The Lancet Child and Adolescent Health journal, show that injecting infants with the antibody 'nirsevimab' reduces risk of RSV-related hospitalisations by 83 per cent and intensive care admissions by 81 per cent. Infant immunisation programmes could, therefore, help address the health and economic burden due to RSV in the high-risk period following birth, a team of researchers from Canada and the US said. RSV, or respiratory syncytial virus, is one of the leading causes of serious respiratory ill-health in the early years of one's life, and is usually prevalent during early winter months.
Globally, the condition is estimated to cause 36 lakh hospitalisations a year among children aged under five, according to the World Health Organization.
Nirsevimab was approved in 2023 by regulatory agencies, including the US' Food and Drug Administration and European Medicines Agency, after the lab-created antibody was found to be safe and effective in clinical trials.
Effectiveness of nirsevimab
Through national programmes, infants in high-income countries, such as in the US and European Union, have been injected with nirsevimab. The researchers said that efficacy of nirsevimab seen in the controlled settings of a clinical trial may not fully reflect how the lab-created antibody performs in real-world settings.
Real-world effectiveness studies are essential to evaluate the effectiveness of nirsevimab across diverse infant populations and clinical settings, the team added. For this study, the researchers analysed 27 previously published studies, which were conducted during the RSV seasons of 2023-2024 across five countries -- France, Italy, Luxembourg, Spain and the US. The team mainly focussed on infants aged under 12 months.
"Nirsevimab is highly effective in preventing RSV-related outcomes in infants, with a pooled real-world effectiveness of 83 per cent against hospitalisation, 81 per cent against ICU admission, and 75 per cent against LRTI (lower respiratory tract infections)," the authors wrote.
The lab-created antibody was also found to be more effective among infants aged over three months, compared to those aged under three months.
Monoclonal is an antibody, not a vaccine
The researchers noted that nirsevimab is not a vaccine, despite being delivered as an injection.
A monoclonal antibody is created in a lab to mimic how an antibody works, whereas a vaccine empowers the body's immune system to produce an immune response, which involves creating antibodies, they said.
The findings indicate that the benefits of nirsevimab seen in clinical trials could be translated into real-world settings, potentially reducing the burden of RSV disease among infants and use of healthcare resources, the authors said.