Norovirus is a highly contagious virus that causes vomiting and diarrhea (acute gastroenteritis). All ages, all people, are susceptible to infection. As vomiting is the most common symptom of norovirus gastroenteritis, so the disease is also known as "winter vomiting disease".

Young children and the elderly are at high risk. In China, the detection rate of norovirus in children under 5 years old with diarrhea is about 15%.

Although infection is possible throughout the year, but autumn and winter is the high incidence of norovirus season.

Norovirus often causes acute gastroenteritis and is a common cause of food poisoning, often associated with the consumption of uncooked shellfish.

People can contract norovirus from contact with infected people, from eating or drinking contaminated food or water, or by touching contaminated surfaces. Norovirus can cause acute gastroenteritis outbreaks in crowded places, such as schools, nursing homes, hotels, playgrounds, and cruise ships.

The most common symptoms are vomiting and diarrhea, followed by nausea, abdominal pain, headache, fever, chills and muscle aches.

Symptoms of acute norovirus gastroenteritis differ between adults and children, with vomiting predominating in children and diarrhea in adults.

Norovirus can be transmitted through the following ways.
Consuming or drinking food or water contaminated with the virus.
Contact with the vomit or feces of a patient.
Contact with contaminated objects.
Transmission via virus-carrying droplets produced during vomiting.

The incubation period for norovirus infection is usually 12 to 48 hours. The maximum duration is 72 hours.

There is no vaccine to prevent norovirus infection, only general preventive measures against gastroenteritis.