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Journal Article Epublish 221 citations

PubMed: 38457312 DOI: 10.15585/mmwr.mm7309a4

Early Estimate of Nirsevimab Effectiveness for Prevention of Respiratory Syncytial Virus-Associated Hospitalization Among Infants Entering Their First Respiratory Syncytial Virus Season - New Vaccine Surveillance Network, October 2023-February 2024.

MMWR Morb Mortal Wkly Rep 73(9):209-214

Authors: Heidi L Moline, Ayzsa Tannis, Ariana P Toepfer, John V Williams, Julie A Boom, Janet A Englund, Natasha B Halasa, Mary Allen Staat, Geoffrey A Weinberg, Rangaraj Selvarangan, Marian G Michaels, Leila C Sahni, Eileen J Klein, Laura S Stewart, Elizabeth P Schlaudecker, Peter G Szilagyi, Jennifer E Schuster, Leah Goldstein, Samar Musa, Pedro A Piedra, Danielle M Zerr, Kristina A Betters, Chelsea Rohlfs, Christina Albertin, Dithi Banerjee, Erin R McKeever, Casey Kalman, Benjamin R Clopper, Meredith L McMorrow, Fatimah S Dawood

Abstract

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among infants in the United States. In August 2023, CDC's Advisory Committee on Immunization Practices recommended nirsevimab, a long-acting monoclonal antibody, for infants aged <8 months to protect against RSV-associated lower respiratory tract infection during their first RSV season and for children aged 8-19 months at increased risk for severe RSV disease. In phase 3 clinical trials, nirsevimab efficacy against RSV-associated lower respiratory tract infection with hospitalization was 81% (95% CI = 62%-90%) through 150 days after receipt; post-introduction effectiveness has not been assessed in the United States. In this analysis, the New Vaccine Surveillance Network evaluated nirsevimab effectiveness against RSV-associated hospitalization among infants in their first RSV season during October 1, 2023-February 29, 2024. Among 699 infants hospitalized with acute respiratory illness, 59 (8%) received nirsevimab ≥7 days before symptom onset. Nirsevimab effectiveness was 90% (95% CI = 75%-96%) against RSV-associated hospitalization with a median time from receipt to symptom onset of 45 days (IQR = 19-76 days). The number of infants who received nirsevimab was too low to stratify by duration from receipt; however, nirsevimab effectiveness is expected to decrease with increasing time after receipt because of antibody decay. Although nirsevimab uptake and the interval from receipt of nirsevimab were limited in this analysis, this early estimate supports the current nirsevimab recommendation for the prevention of severe RSV disease in infants. Infants should be protected by maternal RSV vaccination or infant receipt of nirsevimab.

MeSH

Respiratory Syncytial Viruses, Mortality, Hospitalization, Vaccines, Respiratory Tract Infections, Aged, Viruses, Satellite Viruses, Morbidity, Infections, Infant

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