Table 1. Epidemiological and economics characteristics of various age groups for considering norovirus vaccines ^{1 , 2} .

	Incidence	Health care utilization 3	Hospitalization	Deaths 4	Societal costs	Health care costs	Role/risk in transmission	Challenges in vaccinating: immunological	Challenges in vaccinating: programmatic
Children (<5 years)	High	High	High	Med.	High	High	High	Naïve: may need multiple doses	Interaction with other routine immunizations
Older children (5–14 years)	Med.	Low	Low	Low	Med.	Low	Med.	History of exposure
Younger adults (15–64 years)	Med.	Low	Low	Low	Med.	Low	Med.	History of exposure	Generally low coverage
Older adults (≥65 years)	Low	Med.	High	High	Low	High	Low	History of exposure immune senescence	Generally low coverage

¹ For all groups, revaccination may be required after strain shifts.

² Rankings (low/medium/high) are subjective and relative to norovirus disease only—no comparisons to other diseases are intended.

³ Outpatient, emergency, and ambulatory services

⁴ Little data from lower income settings.