In the past several years, we have used doses of passive antibody to protect infants from respiratory syncytial virus (RSV) infection. Initially, infants at high risk for severe RSV infection, including infants born preterm and those with congenital cardiac disease or chronic lung disease, received monthly doses of palivizumab (Synagis) during the RSV season. Last year, nirsevimab (Beyfortus) was introduced as a single dose injection for this population of high-risk infants It could also be given to healthy infants born at term if their mothers had not received the RSV vaccine prenatally.
Many parents have welcomed the introduction of nirsevimab, but there have also been a lot of questions: Is nirsevimab as good as palivizumab? Is one dose enough?
This week, Pediatrics is early releasing an article and accompanying video abstract entitled, “RSV Neutralizing Antibodies Following Nirsevimab and Palivizumab Dosing,” by Deidre Wilkins, BSc, Ulrika Wählby-Hamrén, PhD, and colleagues from AstraZeneca Pharmaceuticals (manufacturer of Beyfortus), SUNY Upstate-Syracuse, Seattle Children’s Hospital, and Lurie Children’s Hospital (10.1542/peds.2024-067174).
The authors conducted a randomized trial in which infants born preterm and/or with congenital heart disease or chronic lung disease of prematurity received either 1 single dose of nirsevimab (followed by 4 monthly doses of placebo) or 5 monthly doses of palivizumab during 2 consecutive RSV seasons. They collected serum samples to look at concentrations of neutralizing antibody, which is the type that confers immunity to the disease.
While both regimens resulted in protective neutralizing antibody levels, nirsevimab resulted in levels that were 10 times higher and lasted longer than palivizumab.
This is clearly great news for our youngest and smallest patients. While this study sample was quite small, the results are promising that this group, when given a single dose of nirsevimab, will have more robust protection from severe RSV disease and for longer.
