What is Norovirus?

Have you ever had a stomachache that was so bad that it made you nauseated, so that you vomited and had diarrhea all day…and then a couple of days later you were back to normal? You might have had a “stomach bug”! Doctors sometimes use the words “stomach bug” when they are talking about a virus called norovirus. Norovirus can get into the body through food or water, or through contact with another person who is sick, or by touching the surfaces a sick person has been in contact with. The virus then travels to the digestive system and can cause vomiting and diarrhea lasting up to 3 days (Figure 1). Taking care of ourselves, getting lots of sleep, and drinking lots of water can give our bodies the tools they need to fight norovirus infection (Figure 2). Not everyone can fight off norovirus easily, especially in nursing homes and childcare centers where it spreads quickly [1]. There are many types of noroviruses, which makes it difficult for scientists to create a vaccine to protect everyone, like we have for other viruses like measles and mumps.

All over the world, norovirus is the most common germ that causes vomiting and diarrhea, often referred to as gastroenteritis, which means inflammation in the stomach and intestines. Even if you do not feel sick, you can spread norovirus to others. Some people have a higher chance of becoming sicker than others. These people have weaker immune systems, which means their bodies’ natural defenses are not strong enough to fight germs on their own [2]. These groups include children younger than 5, grown-ups older than 65, and patients being treated for diseases such as cancer. Doctors and nurses, who spend a lot of time with sick patients, can also spread norovirus or become sick themselves.

What Does Norovirus Do?

If you become infected with norovirus, you may experience vomiting and diarrhea, as well as a stomachache, a slight fever, and a loss of appetite (Figure 1). Most people have these symptoms for up to 3 days, however, about 50% of those with norovirus do not develop symptoms at all. If symptoms are present, they generally appear a day or two after the person is exposed to norovirus. Doctors do not usually perform specific testing for norovirus because it does not last long in your body, and knowing which virus is there does not change your treatment [3]. In rare cases, you may lose so much water from the illness that you can experience dehydration. This is when you have too little water in your body for your cells to function. If vulnerable people, such as children under 5, grown-ups over 65, and sick patients, catch norovirus, their symptoms can last much longer and leave them feeling worse. They might need to go to the hospital to receive extra care. This is why it is especially important to avoid spreading the virus to these groups (Figure 3) [4].

How Do Doctors Treat Norovirus?

There are no specific medications to treat norovirus, but most people can fight it off anyway! People who are sick with norovirus must make sure to rest and take care of themselves. This includes staying hydrated by drinking lots of water, eating as healthily as possible (which may be limited to high carbohydrate foods between episodes of vomiting), and getting enough sleep. While sick, you may feel tired and not want to play with your friends or family. Once you start feeling better, it is important to wait 2 days before you go back to normal activities. It takes time for the virus to leave your body, and you do not want to spread it to anyone by touching or sharing food and water with them.

When someone has a severe norovirus infection, they may become very dehydrated and a trip to the hospital may be needed. If a patient has developed dehydration and cannot drink fluids normally because they are vomiting, then the medical staff may insert a cannula, which is a tiny straw that enters a vein through the skin. This allows fluids to be given to the patient without the person needing to drink. Medicines to help with fever, such as paracetamol/acetaminophen, and anti-vomiting medications can be used to help ease the symptoms. Once the patient starts feeling better, the doctors will monitor them until they have enough energy, water, and nutrients in their bodies to go home.

How Can We Protect Ourselves and Each Other From Norovirus?

There are many simple ways to protect ourselves and each other from norovirus. Personal hygiene has been proven to help stop norovirus from spreading, especially proper handwashing. A scientific experiment showed that hand washing can reduce norovirus’ ability to infect people by over 80%. This means eight out of 10 people who washed their hands or used hand sanitizer helped to keep others safe from the virus. By simply washing our hands, especially after using the restroom, we can protect each other from illness. We can also stop the spread of norovirus by washing fruits and vegetables before we eat them, and by keeping our distance from vulnerable friends and family when we feel sick [5].

One of the most effective ways to stop any virus is to make a vaccine, which prevents people from getting infected and spreading it. We have vaccines for the flu, chickenpox, and now COVID-19. Scientists are working hard to make a vaccine for norovirus, which may prevent the infection altogether. This job is a challenge because there are so many types of noroviruses [6–8].

The Main Lessons

Norovirus is the leading cause of gastroenteritis in children and older populations. Norovirus can spread very easily, especially in daycare centers and nursing homes. It is important to maintain good hygiene practices to prevent norovirus from spreading to people who are most at risk of getting sick from it. Scientists still have a lot of work to do to make a vaccine happen, which is why, in the meantime, it is so important to focus on preventing the spread of norovirus at home and at school!

Glossary

Viruses: ↑ Tiny organisms that can infect your body and make more copies of themselves, often making you sick.

Digestive System: ↑ Parts of the body including the stomach and intestines that break down food for energy.

Gastroenteritis: ↑ Inflammation of the digestive system, which can cause vomiting, diarrhea, fever, chills, and dehydration.

Immune System: ↑ The body’s natural defense system, which includes white blood cells and the substances they produce that help you fight germs.

Dehydration: ↑ The condition that results when your body does not have enough water. Symptoms include dry mouth, thirst, feeling tired, and headaches.

Carbohydrates: ↑ Substances made up of chains of sugar molecules that provide energy. Foods high in carbohydrates can include grains such as rice, bread and potatoes.

Cannula: ↑ Small tube that is placed in a blood vessel to give a patient fluids and medications directly into the circulation.

Vaccine: ↑ A medicine that prepares your body to fight off germs before they make you sick.

Conflict of Interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.