Abstract Title
Estimates of the Public Health Impact of Norovirus Vaccination for Older Adults in the United States
Presenter
Brandon Patterson, Moderna, Inc.
Co-Author(s)
Ashley E. Davis, PhD, RTI Health Solutions; Michelle Blake, PhD, Moderna Inc; Brandon J. Patterson, PharmD, PhD, Moderna Inc; Mariana Lehoucq, MSPH, RTI Health Solutions; Anita J. Brogan, PhD, RTI Health Solutions; Cheryl McDade, RTI Health Solutions; Katherine B. Carlson, PhD, MPH, Moderna Inc; Ben Lopman, PhD, Emory University; Philip O. Buck, PhD, MPH, Moderna Inc
Abstract Category
Vaccines and immunity
Abstract
Objective: Norovirus (NoV) is a key cause of acute gastroenteritis (AGE), with the greatest disease burden among older adults, young children, and those with underlying medical conditions. In the US, most NoV-AGE deaths occur among older adults. No vaccine for NoV is currently available, but candidates are in development. We assessed the potential public health impact of NoV vaccination, focusing on adults aged ≥60 years in the US.
Methods: A static health-outcomes model with a decision-tree structure and a 1-year time horizon was developed for a hypothetical vaccine (65% efficacy against NoV). NoV-AGE cases (5% annual incidence) could receive NoV-AGE-related care (10-43% medically attended), and hospitalized cases were at risk of NoV-AGE-related mortality. Data to inform NoV-AGE incidence, resource use, and mortality were obtained from published literature, publicly available data, and expert opinion. Health outcomes included NoV-AGE cases, hospitalizations, deaths, and number needed to vaccinate to prevent 1 NoV-AGE case or 1 hospitalization. Sensitivity analyses assessed the impact of parameter uncertainty and modeling assumptions.
Results: The model estimated that among adults aged ≥60 years, vaccination with 50% coverage may prevent 1,315,975 NoV-AGE cases (percentage reduction: 32.5%), 24,420 NoV-AGE hospitalizations, and 552 NoV-AGE-related deaths annually. To prevent 1 NoV-AGE case or hospitalization, 62 or 3,186 older adults need to be vaccinated, respectively. Sensitivity analyses showed results to be robust when varying key parameters.
Conclusions: NoV vaccination may provide significant public health benefits for older adults in the US. Estimates should be refined with updated epidemiological and clinical data as surveillance improves and vaccine development continues.
Methods: A static health-outcomes model with a decision-tree structure and a 1-year time horizon was developed for a hypothetical vaccine (65% efficacy against NoV). NoV-AGE cases (5% annual incidence) could receive NoV-AGE-related care (10-43% medically attended), and hospitalized cases were at risk of NoV-AGE-related mortality. Data to inform NoV-AGE incidence, resource use, and mortality were obtained from published literature, publicly available data, and expert opinion. Health outcomes included NoV-AGE cases, hospitalizations, deaths, and number needed to vaccinate to prevent 1 NoV-AGE case or 1 hospitalization. Sensitivity analyses assessed the impact of parameter uncertainty and modeling assumptions.
Results: The model estimated that among adults aged ≥60 years, vaccination with 50% coverage may prevent 1,315,975 NoV-AGE cases (percentage reduction: 32.5%), 24,420 NoV-AGE hospitalizations, and 552 NoV-AGE-related deaths annually. To prevent 1 NoV-AGE case or hospitalization, 62 or 3,186 older adults need to be vaccinated, respectively. Sensitivity analyses showed results to be robust when varying key parameters.
Conclusions: NoV vaccination may provide significant public health benefits for older adults in the US. Estimates should be refined with updated epidemiological and clinical data as surveillance improves and vaccine development continues.