Table 2. Epidemiological, economic, and programmatic considerations for specific subpopulation risk groups.

	Health care workers	Travelers	Military personnel	Immunocompromised	Food service workers
Incidence	Affected in outbreaks	High	High	Unknown	Likely same as general population
Severe disease	Low risk	Can have limited access to care while traveling	Outbreaks may occur under extreme temperature and exertional conditions	High risk, including chronic infection and death	Low risk
Economic losses and disruption	Productivity losses; compromised patient care from missed work	Loss of personal travel funds, sometimes loss to operators (e.g., cruise industry)	Impact on training, mission readiness, and operations	Costly extended length of hospitalization	Productivity losses from missed work; impact on business of product recall, store closure, or brand impact
Role in transmission and potential indirect benefits of vaccination	May transmit to patients, but current evidence suggests low rates	Generally low, but potential for transmitting on aircraft, buses, hotels, etc.	Potentially high for those resident in barracks, on ships, or on missions	Unknown, but potential risk due to prolonged shedding	High: food handlers implicated in the majority of foodborne norovirus outbreaks
Challenges in vaccinating: immunological	May have extensive history of exposure	Unfamiliar strains during foreign travel	Unfamiliar strains during foreign deployment	Poor immune response	None
Challenges in vaccinating: programmatic	Has taken many years to achieve reasonable influenza vaccine coverage in the United States; Many health care workers do not get vaccinated.	Need to be vaccinated in a travel clinic, with sufficient time to mount immune response before departure	None, but if given in recruit setting, interference with other concomitant immunizations should be assessed	May be difficult to identify in advance of exposure	Hard to reach population with high turnover; unwillingness of employer to pay