Norovirus causes an average of 900 deaths annually mostly among older adults, 109,000 hospitalizations, and 19 million to 21 million cases in the U.S. each year.

Millions of kids have now been vaccinated against rotavirus. Norovirus, by contrast, is famous as the scourge of cruise ships, making hundreds of guests suffer through stomach pain and diarrhea.

State officials are urging residents to wash their hands and take other precautions as New Jersey experiences a surge of the highly contagious norovirus. It's part of a national phenomenon, with ...