2024 Norovirus outbreak in the US; Here's what to know about the virus and its spread

The norovirus is a highly contagious virus that is currently the leading cause of vomiting, diarrhea and  food-borne illness  within the US, the CDC says.

Based on data gathered by the CDC, norovirus activity has been high in 2024, with more outbreaks and laboratory reports than average.  

What is Norovirus?

According to NoroSTAT Data by the CDC, the total number of outbreaks reported during the 2024-2025 seasonal year is well above the range reported within the same period during the 2012-2020 and 2021-2024 seasonal years. It peaked in mid-October of this year, with about 40 reported cases, doubling the average of that same range in previous years.

The norovirus is sometimes referred to as the  "stomach flu," or the "stomach bug,"  but norovirus illness is not related to the flu , says the CDC. The flu is caused by the influenza virus , whereas norovirus cases can cause acute gastroenteritis, which is an inflammation of the stomach or intestines.  

How long does Norovirus last?

According to the CDC, people with norovirus often get better within one to three days. However, they can still spread the virus for a few days afterwards. Someone who has been exposed to norovirus will typically develop symptoms 12 to 48 hours after exposure.

The most common symptoms of norovirus are diarrhea, vomiting, nausea and stomach pain. Other symptoms of norovirus include fever, headache and body aches.

Due to frequent vomiting and diarrhea, norovirus can lead to dehydration. According to the CDC, symptoms of dehydration include decreased urination, dry mouth and throat, feeling dizzy when standing, crying with few or no tears, as well as unusual sleepiness or irritability.

The CDC says that anyone can get infected and become sick with norovirus, and people of all ages can get infected during norovirus outbreaks.

Majority of norovirus outbreaks occur when infected individuals spread the virus to other via direct contact, says the CDC. This can happen when caring for infected individuals, as well as by sharing food or eating utensils. Surfaces that have been contaminated with the norovirus, including food and water, can lead to outbreaks.