Targeting pediatric versus elderly populations for norovirus vaccines: a model-based analysis of mass vaccination options

• Type of Material: Article
• Authors: Molly K. Steele, Centers for Disease Control and Prevention; Justin Remais, Emory University; Manoj Gambhir, Monash University; John W. Glasser, Centers for Disease Control and Prevention; Andreas Handel, University of Georgia; Umesh D. Parashar, Centers for Disease Control and Prevention; Benjamin Lopman, Emory University
• Language: English
• Date: 2016-12-01
• Publisher: Elsevier: Creative Commons Licenses
• Publication Version: Final Published Version
• Copyright Statement: © 2016 The Authors
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.epidem.2016.10.006
• Title of Journal or Parent Work: Epidemics
• ISSN: 1755-4365
• Volume: 17
• Start Page: 42
• End Page: 49
• Grant/Funding Information: This work was partially funded from Emory University's Open Access Publishing Fund.; This work was supported by a NoroCORE Graduate Fellowship funded by the United States Department of Agriculture - National Institute of Food and Agriculture Food Virology Collaborative [to MKS]; a fellowship from the Oak Ridge Institute for Science and Education [to MKS]; the National Institutes of Health/National Institute of Allergy and Infectious Diseases[K01AI091864 to JVR]; the National Science Foundation Water Sustainability and Climate Program [1360330 to JVR]; and the National Institutes of Health/Fogarty International Center [R01TW010286 to JVR].
• Keywords: Science & Technology; PREVALENCE; Life Sciences & Biomedicine; EPIDEMIOLOGY; ENGLAND; Infectious Diseases; ADULTS; ANTIBODIES; Transmission; NORWALK VIRUS; GASTROENTERITIS; UNITED-STATES; Herd immunity; TRANSMISSION; DISEASE; Norovirus; Vaccination; Mathematical modeling
• Research Categories: Health Sciences, Epidemiology; Health Sciences, Public Health

Abstract

Background Noroviruses are the leading cause of acute gastroenteritis and foodborne diarrheal disease in the United States. Norovirus vaccine development has progressed in recent years, but critical questions remain regarding which age groups should be vaccinated to maximize population impact. Methods We developed a deterministic, age-structured compartmental model of norovirus transmission and immunity in the U.S. population. The model was fit to age-specific monthly U.S. hospitalizations between 1996 and 2007. We simulated mass immunization of both pediatric and elderly populations assuming realistic coverages of 90% and 65%, respectively. We considered two mechanism of vaccine action, resulting in lower vaccine efficacy (lVE) between 22% and 43% and higher VE (hVE) of 50%. Results Pediatric vaccination was predicted to avert 33% (95% CI: 27%, 40%) and 60% (95% CI: 49%, 71%) of norovirus episodes among children under five years for lVE and hVE, respectively. Vaccinating the elderly averted 17% (95% CI: 12%, 20%) and 38% (95% CI: 34%, 42%) of cases in 65+ year olds for lVE and hVE, respectively. At a population level, pediatric vaccination was predicted to avert 18–21 times more cases and twice as many deaths per vaccinee compared to elderly vaccination. Conclusions The potential benefits are likely greater for a pediatric program, both via direct protection of vaccinated children and indirect protection of unvaccinated individuals, including adults and the elderly. These findings argue for a clinical development plan that will deliver a vaccine with a safety and efficacy profile suitable for use in children.