Wits University has reported that a drug to prevent respiratory syncytial virus (RSV) in infants is safe and effective, enabling ways to protect vulnerable groups such as preterm babies from the virus.
RSV is a major cause of lower respiratory tract infection (LRTI) and hospitalisation in infants. Globally, approximately one-third of all hospitalisations for lower respiratory tract illness are caused by RSV. Hence, there is a serious unmet medical need for RSV protection in healthy infants born at term.
The Wits Vaccines and Infectious Diseases Analytics (Wits VIDA) research unit was the lead South African collaborator in a phase 2/3 study to investigate the efficacy and safety of Nirsevimab, in healthy late-preterm and term infants.
Nirsevimab is a monoclonal antibody against RSV with an extended half-life. Monoclonal antibodies are antibodies that have a high degree of specificity (mono-specificity) for an antigen or epitope, and are generally well tolerated. Monoclonal antibodies are typically derived from a clonal expansion of antibody-producing malignant human plasma cells. Because they are large proteins (typically 150-200 000 daltons in size) they require parenteral, often intravenous, administration.
Nirsevimab has an extended half-life of three to four months, and is able to provide protection for the entire RSV season, which usually lasts for three to four months.
Compared to term infants, late preterm infants (born at 32 to 37 weeks) have a higher hospitalisation and mortality risk from RSV, due to their relative physiologic and metabolic immaturity. Late preterm infants are at increased risk of a host of morbidities and mortality, including respiratory distress and failure, feeding difficulties, poor growth, hypoglycaemia, hyperbilirubinemia, and hypothermia.
The study, published in the New England Journal of Medicine, found that the drug Nirsevimab significantly protected infants against RSV disease in the Phase 3 MELODY trial, and protected high risk children in a separate study known as MEDLEY.
“This intervention provides the opportunity to protect young infants against the most common cause of hospitalisation from lower respiratory tract infections – RSV – which kills between 60 000 to 190 000 babies each year, mainly in low- and middle-income countries,” says Wits Professor of Vaccinology Shabir Madhi, Director of Wits VIDA, and a co-author of the study.
The findings showed 74.5% efficacy against medically attended lower respiratory tract infections caused by RSV in healthy infants.
Furthermore, Nirsevimab is the first potential immunisation for all infants to demonstrate sustained protection across the entire RSV season with a single dose.
“The new drug provides the opportunity of protecting infants, including high-risk groups – such as those born prematurely or with chronic lung or congenital heart disease – against the leading cause of hospitalisation for lower respiratory tract infections among infants globally,” says Madhi.
Source: Wits University
