The population-level impacts of excluding norovirus infected food workers: a mathematical modeling study

Abstract

Norovirus is the leading cause of acute gastroenteritis and of foodborne disease in the United States. The Food and Drug Administration recommends foodworkers infected with norovirus be excluded from work while symptomatic and 48 hours after their symptoms subside. Compliance with this recommendation is not ideal and the population-level impacts of changes in foodworker compliance have yet to be quantified. We aimed to assess population impacts of varying degrees of compliance with the current recommendation through a compartmental model. We modeled the number and proportion of symptomatic norovirus cases averted in the U.S. population, by specific age ranges (0–4 year-olds, 5–17 year-olds, 18–64 year-olds, and 65+ year-olds), under various scenarios of foodworker exclusion (i.e., proportion compliant and days of post-symptomatic exclusion) compared to a referent scenario, which assumes 66.6̅% of norovirus symptomatic foodworkers and 0% of post-symptomatic foodworkers are excluded. Overall, we estimated 6.0 million norovirus cases have already been avoided annually under the referent scenario and 6.7 million (28%) more cases may be avoided through 100% compliance with the current recommendations. Substantial population-level benefits were predicted from improved compliance in exclusion of norovirus infected foodworkers – benefits that may be realized through policies or programs incentivizing self-exclusion.