What Are the Symptoms of Norovirus?
CDC says norovirus can make you feel extremely ill and vomit or have diarrhea many times a day, which can lead to dehydration, especially in older adults and people with other illnesses. It says a person usually develops symptoms 12 to 48 hours after being exposed, and that most people get better within 1 to 3 days but can still spread the virus for a few days after.
It spreads easily. CDC says a sick person can shed billions of norovirus particles that cannot be seen without a microscope, and that it takes only a few particles to make other people sick. It reports about 2,500 norovirus outbreaks in the United States each year, occurring throughout the year but most commonly from November to April.
Wash hands and disinfect. CDC says hand sanitizer does not work well against norovirus, and that it can be used in addition to handwashing but is not a substitute for it. To disinfect, it recommends a chlorine bleach solution with a concentration of 1,000 to 5,000 parts per million, which is 5 to 25 tablespoons of household bleach per gallon of water.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceCDC says a person usually develops norovirus symptoms 12 to 48 hours after being exposed to the virus. CDC ↗
- Government sourceCDC says most people with norovirus get better within 1 to 3 days, but can still spread the virus for a few days afterward. CDC ↗
- Government sourceCDC says norovirus can cause vomiting or diarrhea many times a day, which can lead to dehydration, especially in older adults and people with other illnesses. CDC ↗
- Government sourceCDC says a person with norovirus can shed billions of virus particles, and only a few particles are enough to make other people sick. CDC ↗
- Government sourceCDC says hand sanitizer does not work well against norovirus, and is not a substitute for handwashing. CDC ↗
- Government sourceCDC recommends disinfecting after norovirus with a chlorine bleach solution of 1,000 to 5,000 ppm, or 5 to 25 tablespoons of household bleach per gallon of water. CDC ↗
- Government sourceCDC reports about 2,500 norovirus outbreaks in the United States each year, most common from November to April. CDC ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.