Rotavirus vs. norovirus vs. stomach flu: Compare causes, symptoms, treatments & more

Causes | Similarities | Prevalence | Symptoms | Diagnosis | Treatments | Risk factors | Prevention | When to see a doctor | FAQs | Resources

Nausea, vomiting, diarrhea—most people refer to these symptoms as having a “stomach bug” or “stomach flu,” but the medical term for the stomach flu is viral gastroenteritis.

Gastroenteritis is an inflammation of your intestines—over 20 million people in the U.S. experience this illness every year. The stomach flu, or viral gastroenteritis, is most often caused by viruses. However, the viruses that cause stomach flu are not the same as those that cause influenza (the flu that causes fever, body pains, and respiratory symptoms). 

Two common causes of viral gastroenteritis are rotavirus and norovirus. Adenovirus, sapovirus, and astrovirus are other viruses that can cause stomach problems but are less common than rotavirus and norovirus. 

Rotavirus is a virus that causes gastrointestinal symptoms, primarily in infants and young children. The rotavirus vaccine can prevent rotavirus. 

Norovirus is a common virus that can cause gastroenteritis. Norovirus is the most common cause of vomiting, diarrhea, and foodborne illness. In this article, we will discuss rotavirus and norovirus. They have many similarities as well as many differences. Continue reading to learn all about rotavirus and norovirus.

Causes

Rotavirus

Rotaviruses are wheel-shaped RNA viruses that belong to a family called Reoviridae. 

In most cases, rotavirus spreads from fecal-oral contact. When a person is infected with rotavirus, the virus is shed in the stool. The virus can then infect others. For example, a person may not wash their hands well, and then puts food in their mouth and/or handles food that someone else eats. Or, someone may touch a surface (the virus can live on surfaces for a while) that is contaminated and put their fingers in the mouth. In less common cases, the virus can be spread by sneezing or coughing.

Norovirus

Noroviruses are RNA viruses that belong to the Caliciviridae family and are sometimes referred to as the Norwalk virus. According to the U.S. Centers for Disease Control and Prevention (CDC), if you think you have a stomach bug, stomach flu, or food poisoning, it is likely caused by norovirus.

People with norovirus shed billions of microscopic particles in feces or vomit that are very contagious. It only takes a few particles to get sick. Food can be contaminated with norovirus in several ways, such as when an infected person has feces or vomit particles on their hands and then touches food, or when food is placed on a surface with particles of feces or vomit on it. Most outbreaks occur in food service settings. Water can also become contaminated with norovirus. Surfaces can become infected as well, for example, when an infected person has feces or vomit particles on their hands and touches a surface, or when contaminated food or water is placed on a surface.

Similarities and differences between rotavirus and norovirus

Rotavirus and norovirus have some similarities. Both are stomach illnesses that cause symptoms such as vomiting, diarrhea, and stomach pain. Both illnessess are usually diagnosed based on symptoms alone. There is no cure for either virus. Healthcare providers will recommend trying to prevent or treat dehydration. Both viruses can cause severe dehydration, which may require a hospital stay.

Rotavirus and norovirus also have some differences. While rotavirus occurs mostly in infants and young children, norovirus can occur at any age. Rotavirus has a vaccine that prevents the virus, making illness very rare in the United States. On the other hand, there is no vaccine for norovirus, and it is very common in the US. Symptoms of rotavirus last from 3-8 days, while symptoms of norovirus generally last 1-3 days.

Prevalence

Rotavirus

In the U.S., rotavirus vaccines are very effective in preventing rotavirus. Before the vaccines were developed, rotavirus caused 2 to 3 million illnesses yearly, with up to 70,000 requiring hospitalization. Now, severe illness from rotavirus is rare in the U.S. Rotavirus is mostly seen in children under 5 years of age. 

Looking at the epidemiology throughout the world, rotavirus causes more than 125 million cases of diarrhea in infants every year. Over 2 million children under 5 years old are hospitalized every year due to rotavirus symptoms. Of these, about half a million children die. 

Norovirus

There are about 19-21 million cases of acute gastroenteritis (stomach and/or intestinal inflammation) in the U.S. due to norovirus every year. Death is very rare. Approximately 570-800 people die yearly from norovirus, mostly young children or older adults, who are vulnerable to severe dehydration. Norovirus can occur any time of year but is most common in the winter. Norovirus outbreaks have occurred in various settings such as restaurants, health care facilities, schools, cruise ships, military ships, and resorts. Norovirus can occur at any age.

Worldwide incidence is not well known in developing countries. In industrial countries, the incidence is similar to the U.S.

Symptoms

Rotavirus

The most common symptoms of rotavirus are severe diarrhea, vomiting, fever, and/or stomach pain. Symptoms typically start two days after exposure to the virus. Symptoms can last three to eight days. 

Other symptoms may include appetite loss and dehydration. Dehydration can be very dangerous for infants and young children. Dehydration symptoms include decreased urination, dry mouth, extreme thirst, dizziness when standing up, crying with little or no tears, and being unusually sleepy or fussy. 

Norovirus

The most common symptoms of norovirus are nausea, vomiting, diarrhea, and abdominal pain. Other symptoms may include fever, headache, and body aches. Symptoms generally occur 12 to 48 hours after norovirus exposure. Norovirus symptoms last for about one to three days. When a person has diarrhea or vomits many times a day, dehydration may occur. Dehydration from norovirus is more common in young children, older adults, and those with other medical conditions. 

Diagnosis

Rotavirus

Contact a pediatrician if your child is experiencing symptoms such as fever, diarrhea, stomach pain, and/or vomiting. A diagnosis can often be made based on symptoms and an examination. In some cases, the healthcare provider may ask for a stool sample.  

Norovirus

In most cases, the doctor can diagnose norovirus from your symptoms. A stool sample can confirm the diagnosis but is usually not needed.

Treatments

Antibiotics are never used to treat rotavirus or norovirus infections. Antibiotics are for bacterial infectious diseases only and will not help a viral infection. Contact a healthcare provider if you or the person you are caring for shows symptoms of dehydration, such as dry mouth, decreased urination, and dizziness when standing up. Young children, older adults, and people who have other medical conditions are at higher risk of dehydration.  

Rotavirus

There is not a specific medication that treats rotavirus. Rotavirus can cause severe diarrhea and vomiting, which can lead to dehydration. Taking in plenty of liquids helps to prevent dehydration. Oral rehydration solutions can be useful for mild dehydration, while severe dehydration may require hospitalization and IV fluids. Resting, staying home, and frequent handwashing are important as well. 

Norovirus

There is no specific medication to treat norovirus. Drinking plenty of fluids will help prevent dehydration. Those with mild dehydration can drink oral rehydration solutions, while those with severe dehydration may require IV fluids in the hospital. Try to rest, stay home to avoid spreading infection, and wash hands frequently. 

Risk factors

Rotavirus

In the U.S., children are at the highest risk of getting rotavirus. Children in daycare settings or schools with many young children are at higher risk. The most severe disease occurs in unvaccinated children ages 3 months of age to 3 years old. Some adults are at higher risk. Adults at higher risk are older adults, people caring for a child with rotavirus, and people with compromised immune systems. 

Norovirus

People who have direct contact with an infected person (such as healthcare providers, visitors, or other patients) are at higher risk of getting norovirus. Other risk factors are eating or drinking contaminated foods or liquids or touching contaminated objects or surfaces then touching the mouth. 

Prevention

Rotavirus

The most effective prevention against rotavirus is with the rotavirus vaccine. Most children (about 90%) who are vaccinated with the rotavirus vaccine will be protected from severe illness, and about 70% will be completely protected from rotavirus disease. 

There are two rotavirus vaccines available in the U.S. The first dose should be given before 15 weeks, and all doses should be complete by eight months of age. The vaccines are given by placing oral drops in the baby’s mouth. 

• RotaTeq is given at 2 months, 4 months, and 6 months of age (3 doses)
• Rotarix is given at 2 months and 4 months of age (2 doses)

Although the vaccine is the absolute best line of defense against rotavirus, handwashing can also help prevent the spread of infection. However, handwashing is not a substitute for rotavirus vaccination.

Norovirus

There is a lot of helpful information from the CDC recommending several ways to prevent norovirus. These include:

• Handwashing: Wash hands thoroughly (for at least 30 seconds) with soap and water, especially after using the bathroom, after changing diapers, before eating or preparing food, and before taking medicine or giving someone medicine. Hand sanitizers may be used as well but should not be used as a substitute for soap and water, as they are not as effective at removing virus particles. 
• Food safety: Wash produce carefully. Cook shellfish thoroughly. Foods that may be contaminated should be discarded. People who are sick should be kept out of areas where food is being prepared. 
• Do not care for others when sick: When you are ill and for at least two days after symptoms stop, do not prepare food for others or take care of others.
• Clean and disinfect surfaces: When someone has diarrhea or vomits, clean and disinfect the entire area while wearing gloves. Wipe with paper towels, then disinfect with a bleach-based cleaner. Leave the cleaner on the area for at least 5 minutes, then clean again with soap and hot water. Clean and sanitize kitchen utensils and surfaces. 
• Wash laundry thoroughly: Clothes or bedding that may be contaminated with feces or vomit should be immediately removed or washed. Handle items with gloves, wash items in hot water, and dry on the highest heat setting—wash hands after handling soiled items. 

When to see a doctor for rotavirus or norovirus

If you are an adult with gastrointestinal symptoms, contact your doctor if you have been vomiting for more than two days or are vomiting blood, have bloody stools, are dehydrated, or have a fever of 104 F or above. 

If your child is ill, call a pediatrician or seek emergency care if your child has a fever of 102 F or higher, is very lethargic or cranky, is in pain, has blood in the stools, or seems dehydrated. Even if symptoms are not severe, it is always a good idea to report symptoms to the pediatrician so they can provide medical guidance.   

Infants who are vomiting, dehydrated, have bloody stools or severe diarrhea, or are unusually sleepy should be seen by the doctor immediately or receive emergency medical care. In infants, as with children, even if symptoms are not severe, it is a good idea to check in with a pediatrician to report symptoms and receive medical guidance. 

Nausea, vomiting, and diarrhea can also be symptoms of COVID-19 (coronavirus), so you may also want to check with your healthcare provider to see if you need a COVID test, especially if you have been exposed to COVID. 

Frequently asked questions about rotavirus vs. norovirus

Are norovirus and rotavirus the same thing?

Norovirus and rotavirus are different viruses that cause stomach problems, like nausea, vomiting, and diarrhea. Norovirus is more common in adults, while rotavirus tends to affect infants and young children. There is a vaccine to prevent rotavirus, but there is no vaccine to prevent norovirus. There is no cure for either virus. Treatment focuses on hydration— severe cases may require hospitalization. 

What are the common rotavirus symptoms?

The most common rotavirus symptoms are severe, watery diarrhea, vomiting, fever, and stomach pain. Symptoms last anywhere between three to eight days. Other symptoms may include loss of appetite and dehydration. Dehydration can be very dangerous for young children and infants. 

What is the difference between gastroenteritis vs. norovirus?

When someone says they have the stomach flu, they are generally referring to gastroenteritis and they are experiencing symptoms like nausea, vomiting, and diarrhea. Various viruses may cause viral gastroenteritis. Norovirus is the most common cause of gastroenteritis in adults. 

What is the difference between rotavirus vs. stomach bug?

The stomach bug, or stomach flu, as many people call it, is also known as viral gastroenteritis. Different viruses may cause viral gastroenteritis. Rotavirus is a cause of gastroenteritis that mainly affects infants and young children (under 5 years old). So, rotavirus causes gastroenteritis, but gastroenteritis can be caused by different viruses, one of which is rotavirus.

How long is the norovirus contagious period?

According to the CDC, people with norovirus are most contagious while symptoms are present and during the first few days after recovering. However, some studies have shown that norovirus may still be spread for 2 weeks—or longer—after symptoms are gone. 

What’s the difference between norovirus and gastroenteritis?

Gastroenteritis is an inflammation of the stomach and intestine lining that causes stomach symptoms such as vomiting and diarrhea. Norovirus is one type of virus that can cause gastroenteritis.  

Can adults get rotavirus? 

Although rotavirus most often occurs in infants and young children, older children and adults can get rotavirus. However, rotavirus is very rare in the US due to the vaccine. Adults who do get rotavirus usually have more mild symptoms. Older adults, adults who care for a child with rotavirus, and immunocompromised adults are at higher risk for rotavirus. 

What are the first signs of norovirus?

The first, and most common, signs of norovirus are nausea, vomiting, diarrhea, and stomach pain. 

What does rotavirus smell like?

Rotavirus diarrhea is described as “foul-smelling,” and tends to be watery and/or green.

Resources

• Gastroenteritis in children, American Family Physician
• Nausea and vomiting, Cleveland Clinic
• Norovirus, Cleveland Clinic
• Norovirus, Medscape
• Norovirus, U.S. Centers for Disease Control and Prevention
• Prevention of diarrheal illness, Oklahoma State Department of Health
• Rotavirus, Cleveland Clinic
• Rotavirus, Medscape
• Rotavirus, U.S. Centers for Disease Control and Prevention
• Rotavirus infections, Boston Children’s Hospital
• Rotaviruses, noroviruses, and other gastrointestinal viruses, U.S. National Library of Medicine
• Rotavirus questions and answers, Immunization Action Coalition
• Stomach flu (gastroenteritis), Cleveland Clinic
• Viral gastroenteritis, National Center for Biotechnology Information