Disease & Vaccine A–Z

Diseases beginning with N

U.S.-focused summaries with current official guidance links. For a diagnosis, personal vaccine schedule, pregnancy advice, or urgent symptoms, speak with a qualified clinician.

Norovirus

No vaccine available

Disease

A very contagious virus that causes acute inflammation of the stomach and intestines.

Symptoms

Sudden diarrhea, vomiting, nausea, and stomach pain; fever, headache, or body aches can also occur. Dehydration is the main concern, especially for young children, older adults, and medically fragile people.

Typical duration

Symptoms usually begin 12 to 48 hours after exposure and most people improve within 1 to 3 days, although they may continue spreading virus after they feel better.

How serious is it?

Most illness is brief, but severe dehydration can require emergency or hospital treatment. Seek care for very little urination, marked sleepiness, dizziness, inability to keep fluids down, blood in stool, or worsening symptoms.

Treatment & management

There is no norovirus-specific medicine. Replace fluids and electrolytes; severe dehydration may require intravenous fluids. Antibiotics do not work against viruses.

Vaccine: who and when?

No norovirus vaccine is licensed in the United States. Vaccine candidates are being studied.

Check the current CDC guidance for Norovirus →

Cost and access: Patient cost varies by insurance, provider, location, and eligibility. Many recommended vaccines are covered with no out-of-pocket cost under qualifying plans, and eligible children may receive vaccines through the Vaccines for Children program. CDC price lists are purchasing benchmarks—not guaranteed patient prices. CDC price and program context.

Last reviewed against official U.S. sources: September 5, 2026. This page provides general education, not medical advice.