But with 19 to 21 million illnesses each year in the United States, norovirus nevertheless causes on average 900 deaths and 109,000 hospitalizations annually, mostly among adults aged 65 and older. It also leads to 465,000 emergency department visits, mostly involving young children.

People of all ages can get infected and fall sick from norovirus. Young children, older people and those with weakened immune systems are most at risk, with dehydration from vomiting and diarrhea the top concern.

There is no medication to treat norovirus. Rehydration is recommended by drinking water and other liquids, with the exception of coffee, tea and alcohol.