Every year, we have our peak of respiratory viruses – traditionally influenza, respiratory syncytial virus, and their accompanying lessor demons. These are each awful, of course, in their own way from a patient- and parent-oriented standpoint, but they’re also quite awful at the population level, overburdening limited pediatric and emergency department resources. RSV, in particular, is a vicious scourge of young and vulnerable infants.
The story told here – sponsored by Sanofi – is one of nirsevimab, a monoclonal antibody protein featured last year in the NEJM. Nirsevimab is the evolution of palivizumab, previously approved and used as a multi-injection prophylaxis scheme for the highest-risk infants. The generally established advantages of nirsevimab over palivizumab are higher and longer levels of neutralizing antibodies, requiring only a single injection rather than a multi-dose course. Nirsevimab has been recommended by the Advisory Committee on Immunization Practices for infants in the U.S. since August 2023.
These data give us a wee look at what happens to a country that adopts such a practice of wide immunization with nirsevimab – Spain! These authors compare the burden of lower respiratory tract infections and bronchiolitis admissions at 15 pediatric emergency departments across 2018 to 2024, with 2023-24 being the first season where nirsevimab was in wide usage. Most regions used a strategy in which nirsevimab was provided to new births during RSV season, as well as other young infants born prior to the onset of the season. The two “COVID seasons” of 2020-21 and 2021-22 were excluded from their comparisons.
Generally speaking, the administration of nirsevimab diminished lower respiratory tract infection presentations, bronchiolitis presentations, and bronchiolitis admission by approximately 60% as compared to prior years. The overall effect of these reductions in bronchiolitis presentations had the net effect of decreasing all presentations to the ED by about 20%. I suspect virtually every emergency department and PICU out there would prefer this sort of an experience each winter.
The catch: nirsevimab costs ~USD$500 per dose. The initial ACIP cost-effectiveness evaluations were based on the assumption nirsevimab would be priced at ~$300 a dose, at which point it was considered cost-effective. Obviously, $500 is more than $300 – and thus it becomes a robust debate which infants should be offered nirsevimab with many inputs, assumptions, and remaining uncertainties. The promise is certainly out there, however, of dramatically improved respiratory virus seasons for those working in the emergency department.
“Nirsevimab and Acute Bronchiolitis Episodes in Pediatric Emergency Departments”
https://publications.aap.org/pediatrics/article/doi/10.1542/peds.2024-066584/199339/Nirsevimab-and-Acute-Bronchiolitis-Episodes-in
Nice summary. Thanks for keeping us in the loop!