Norovirus

Norovirus, often mistakenly called the "stomach flu," is a highly contagious viral infection that causes severe gastrointestinal symptoms. It is the leading cause of vomiting, diarrhea, and foodborne illness in the United States. Every year, more than 19 million people are infected with the virus, contributing to over 56,000 hospitalizations and more than 570 deaths. ⁽¹⁾

Norovirus spreads rapidly through contaminated food, water, surfaces, or direct contact with infected individuals. The virus is particularly problematic in closed environments such as schools, nursing homes, and cruise ships, where it can quickly affect large groups of people. ⁽²⁾

Symptoms ⁽²⁾

Symptoms appear 12-48 hours after exposure and include:

• Severe vomiting
• Watery diarrhea
• Stomach cramps
• Nausea
• Low-grade fever
• Muscle pain

Most people experience symptoms for approximately 44 hours, regardless of age or environmental setting. However, infected individuals can remain contagious for several days to weeks after symptoms subside.

Transmission ⁽²⁾

The virus spreads through multiple routes:

• Consuming contaminated food or water
• Touching contaminated surfaces and then touching your mouth
• Direct contact with infected individuals
• Exposure to viral particles from vomit or feces

What makes norovirus particularly challenging is that it only takes a few viral particles to cause infection, and infected people can shed billions of these particles.

Prevention Strategies ⁽²⁾

Note: Antibacterial hand gels, even those with alcohol, are ineffective against killing norovirus.

After someone vomits or has diarrhea, or surfaces have become contaminated:

• Wear rubber or disposable gloves and wipe the entire area with paper towels. Dispose of them in a plastic bag.
• To disinfect, use a chlorine bleach solution with a concentration of 1,000 to 5,000 ppm (5 to 25 tablespoons of household bleach [5% to 8%] per gallon of water) or use an EPA-registered disinfecting product against norovirus.
• Leave bleach disinfectant on the affected area for at least 5 minutes.
• Clean the entire area again with soap and hot water.

How to handle laundry

• Immediately remove and wash clothes or linens that may have vomit or feces on them.
• Wear rubber or disposable gloves.
• Handle items carefully without shaking them.
• Wash the items with detergent and hot water at the maximum available cycle length and then machine dry them at the highest heat setting.
• Wash your hands with soap and water afterward.

Treatment and Management ⁽²⁾

There is no specific treatment for norovirus infection. Since it is a virus, antibiotics are ineffective. The focus is on managing symptoms and preventing dehydration:

• Stay hydrated by drinking plenty of fluids. Sip on broth or fruit juice as tolerated.
• Rest and allow the body to fight the infection.

Monitor for signs of severe dehydration, especially in young children and the elderly:

Children

• No tears when crying
• Lethargy
• Sunken eyes
• Cool, discolored hands and feet
• Wrinkled skin
• No urination for 12+ hours
• Rapid breathing and heartbeat
• Excessive fussiness or sleepiness
• Confusion or disorientation
• Passing out

Adults

• Dark or amber-colored urine
• Little to no urination
• Dry, shriveled skin
• Extreme thirst
• Rapid heartbeat
• Rapid breathing
• Dizziness or lightheadedness
• Confusion or delirium
• Irritability
• Shock (inadequate blood flow)
• Unconsciousness

Seek medical attention if symptoms become severe or dehydration occurs. Luckily, norovirus usually resolves within a few days. Do not use antidiarrheal medication unless instructed by your medical provider, as it slows the evacuation of the virus and can cause it to linger longer.

References

1. Piedmont Healthcare. (2024). Norovirus 101: What you need to know.
2. Centers for Disease Control and Prevention. (2024). About norovirus.
   

Written By Brooke Lounsbury