Acute Gastroenteritis Among Household Contacts of Children with Severe Norovirus Gastroenteritis, United States, 2011-2016

Norovirus-associated acute gastroenteritis (AGE) in children <11 years resulted in substantial AGE illness among household contacts (HHCs). Vomiting (≥5 episodes in 24 hours) was the greatest risk factor (aOR, 2.85, [95% CI, 1.91-4.26]) for AGE symptoms among HHCs of norovirus-positive index cases. HHCs age 0-4 years had the highest attack rates (22%).