Norovirus is a highly contagious virus and a leading cause of gastroenteritis in the United States. Understanding how it spreads, the symptoms it causes, and ways to reduce your risk can help protect your health and the health of those around you.

What Is Norovirus?

Norovirus is a common and contagious virus that causes inflammation of the stomach and intestines, known as gastroenteritis. It causes severe vomiting and diarrhea. Norovirus spreads through close contact with an infected person or by touching contaminated food, water, or surfaces. The virus usually runs its course in 1-3 days. Norovirus is the primary cause of foodborne illness in the US.

Norovirus vs. the Stomach Flu

Norovirus is sometimes mistakenly referred to as “stomach flu.” Norovirus symptoms are due to gastroenteritis, which is inflammation of the stomach and intestines. The influenza virus causes respiratory flu, not gastroenteritis.

Types of Norovirus

There are several types or strains of norovirus. Specifically, there are 48 types that are categorized into 10 different groups. The most common type is GII.4.

Norovirus Symptoms

There are several different symptoms of norovirus, which range in severity. Symptoms tend to appear 12-48 hours after exposure and last 1-3 days. Common symptoms include:

• Nausea
• Vomiting
• Diarrhea
• Stomach cramping
• Stomach pain
• Muscle or body aches
• Headache
• Fever

Common Causes of Norovirus

Norovirus is highly contagious and spreads easily to others. It is caused by a virus under the umbrella of Caliciviridae viruses. The virus causes inflammation of the stomach and intestines, known as gastroenteritis. Typically, it is caused or spread by coming into close contact with an infected person or eating or drinking contaminated food or water or touching a contaminated surface.

How Contagious is Norovirus?

Norovirus is highly contagious and spreads easily between people. A person who is contagious sheds billions of tiny virus particles and it only takes a few of those particles to infect someone. Once you have been exposed to the virus, it takes 12-48 hours for symptoms to appear. Even after symptoms stop, you can still be contagious for up to 48 hours.

Norovirus Risk Factors

Anyone can become infected with norovirus. There are several risk factors for contracting norovirus. Risk factors include:

• Being in close contact with someone who is infected with norovirus.
• Eating contaminated food.
• Drinking contaminated water.
• Touching a contaminated surface.
• Working in a long-term care facility.
• Being on a cruise ship, at a resort, preschool, daycare center, or at any event where people are spending sustained time in close proximity to each other.

Complications with Norovirus

Most people recover from norovirus without complications or long-term issues. However, young children, the elderly, or those with weakened immune systems may be more prone to complications. The main complication from norovirus is dehydration. Severe dehydration can be dangerous, or in some cases, fatal. Signs of dehydration include:

• Fatigue
• Decreased urine output
• Dark colored urine
• Dry mouth
• Dizziness
• Weakness
• Restlessness
• Headache

For children, it may look like fussiness, daytime drowsiness, or crying with little to no tears.

When to Contact Your Doctor

Norovirus usually resolves in 1-3 days. However, if you are unable to eat or drink anything during that time, you should contact your doctor. Dehydration can become a serious or life-threatening condition if left untreated. Additionally, if your symptoms are not resolved in 3 days, it is recommended to contact your doctor.

Diagnosing Norovirus

Typically, norovirus is diagnosed by assessing your symptoms. However, for some people with underlying medical conditions or weakened immune systems, your doctor may want to take a stool sample to confirm a diagnosis of norovirus.

Norovirus Treatment Options

There are no treatments that cure norovirus or immediately stop symptoms. Treatment focuses on relieving symptoms and replenishing the fluid that has been lost and allowing time for your body to rest and recover. Symptoms should subside within 1-3 days. Common treatments include:

• Replenishing fluids
• Rest
• Eating soft and bland foods

Replenishing fluids means especially drinking liquids that contain electrolytes.

Prevention

There are several ways to prevent yourself from getting norovirus. Preventative measures may include:

• Regularly and thoroughly washing your hands with soap and water.
• Avoiding contact with infected individuals.
• Washing your food before eating it (fruits and vegetables).
• Cooking your food to appropriate temperatures (especially seafood and shellfish).
• Sanitizing and cleaning surfaces, objects, and fabrics that are frequently used or touched.
• Regularly and thoroughly wash clothes, especially if soiled.

It is important to note that hand sanitizer does not kill norovirus, only soap and water. If you are infected with norovirus, please do not prepare food for others or care for others, as you are highly contagious.

Norovirus FAQs

How Long is Norovirus Contagious?

Norovirus is contagious for up to 48 hours after your symptoms are gone.

How Long to Recover from Norovirus?

Most people recover from norovirus in 1-3 days. However, some people who become severely dehydrated or have weakened immune systems may take longer to recover.

How to Prevent the Spread of Norovirus?

There are several ways to prevent norovirus from spreading. Preventative measures may include:

• Regularly and thoroughly washing your hands with soap and water.
• Avoiding contact with infected individuals.
• Washing your food before eating it (fruits and vegetables).
• Cooking your food to appropriate temperatures (especially seafood and shellfish).
• Sanitizing and cleaning surfaces, objects, and fabrics that are frequently used or touched.
• Regularly and thoroughly wash clothes, especially if soiled.

It is important to note that hand sanitizer does not kill norovirus, only soap and water. If you are infected with norovirus, please do not prepare food for others, care for others, or be around people for sustained amounts of time. If you must be around someone, it is recommended to stay at a distance and in a mask, if possible.