Written by Hannah Harp
Spoon Feed
Despite introduction of nirsevimab and maternal RSV vaccination, rates of RSV respiratory infection remain high, without significant change in 2023-2024.
Moving the needle on RSV
RSV is the leading cause of hospitalization of infants. We covered a study of nirsevimab efficacy yesterday. Here is another look. Two new preventative measures, nirsevimab, a monoclonal antibody for infants, and an RSV vaccine for pregnant women were released in Sept. 2023. A prospective, population-based surveillance study was conducted across seven U.S. pediatric centers from 2017-2020, and 2023-2024, employing systematic RSV testing and a test-negative case-control design. 28,689 children < 5 presenting to any healthcare setting with acute respiratory infection (ARI) were enrolled. RSV-associated hospitalization rates in 2023-2024 were 5.0 per 1,000 children under 5 years (95%CI 4.6-5.3), with the highest incidence in 0-2 month-olds (26.6 per 1000, 95%CI 23.0-30.2), similar to pre-pandemic rates. While rates of mechanical ventilation for RSV were lower in 2023-2024 (2.3% vs. 4%, p=0.035), there were higher rates of oxygen supplementation (76.9% vs. 63.6%, p<0.001) and ICU admission (24.9% vs. 21.8%, p=0.005). Only 14% of infants in their first RSV season received nirsevimab and just 4% were born to RSV-vaccinated mothers. Estimated nirsevimab effectiveness was 89% (95%CI 79%-94%) against medically-attending RSV-associated ARI and 93% (95%CI 82%-97%) against RSV-related hospitalization. No new mutations in nirsevimab binding were discovered. Unfortunately, this study was limited by the lack of nirsevimab availability, low uptake, and short time frame since release. The uptake of maternal RSV vaccine was too low to analyze for effectiveness.
How will this change my practice?
Our community health center wasn’t able to offer nirsevimab last year and still can’t offer Abrysvo to pregnant women. I’m excited to see how these numbers change as equitable uptake improves.
Editors note: I am fortunate to be in an area where we have nirsevimab available in most pediatric settings, but Hannah’s comment is a good reality check that, unfortunately, this is not the case everywhere. I hope availability and uptake will improve in the coming years, and I will continue to offer nirsevimab to any of my patients who are eligible. -Kelsey Hart
Source
Respiratory Syncytial Virus Disease Burden and Nirsevimab Effectiveness in Young Children From 2023-2024. JAMA Pediatr. 2024 Dec 9:e245572. doi: 10.1001/jamapediatrics.2024.5572. Epub ahead of print. PMID: 39652359; PMCID: PMC11667569.
