Healthy Living

The stomach bug: Why soap is better than hand sanitizer to prevent norovirus

Nov. 16, 2023

Most everyone has experienced the dreaded stomach bug at some point. When your child comes home with it from school, it can feel like it’s inevitable that the whole household will come down with it. Why is norovirus, also known as the “stomach bug,” so contagious? Is there any way to avoid it?

UR Medicine infectious disease expert Brenda Tesini, MD, explains the most important things to do to help keep norovirus from spreading.

What is norovirus?

Norovirus is a group of viruses that cause vomiting and diarrhea. It’s the leading cause of these symptoms in the United States. Norovirus is best known for causing outbreaks on cruise ships but can also spread in many group settings like daycares, schools, and nursing homes.

Norovirus is extremely contagious. People who are sick with it can release billions of virus particles, and it takes less than 100 of those particles to infect someone else. Plus, the virus can stay on objects or surfaces for days and is hard to clean off completely.

How long is norovirus contagious?

A person can be contagious for two to three days after they start to feel better. Symptoms generally show up between 12 and 48 hours after exposure.

Norovirus is commonly referred to as the “stomach flu,” but it’s a completely different virus from the one that causes actual flu. It can also be confused with food poisoning because they have similar symptoms, and both can spread through contaminated food.

What’s the best way to prevent a stomach bug from spreading? 

Hand washing is the most important thing. The germs that cause norovirus can’t be killed by hand sanitizer. Always use soap and water and wash thoroughly.

When you’re handling contaminated objects or surfaces, wear disposable gloves. Be sure to wash soiled clothes and linens immediately in hot water. Frequently clean surfaces and objects that the sick person has touched using either a chlorine bleach solution with at least 5.25% bleach or a product approved by the EPA for norovirus.

How often should I wash my hands?

It’s less about how often you wash them and more about when you wash them. Be sure to wash your hands:


  • Using the bathroom
  • Direct contact with someone who’s sick (like helping your sick child)
  • Cleaning dirty clothes or linens
  • Cleaning the house or space around the sick person


  • Preparing food
  • Eating food
  • Drinking
  • Putting in contacts
  • Anything that requires touching your face

For more detailed info on hand-washing, view the Centers for Disease Control’s guidance: