Introduction

Norovirus is commonly referred to as the stomach flu and generally causes unpleasant symptoms that usually resolve within a few days. Generally, there are no serious symptoms. However, for individuals who have a weaker immune system, norovirus can cause complications that put your health at greater risk. This article will explore what norovirus is and how it impacts those who have a weak immune system.

What is norovirus?

It is a highly infectious virus that causes gastroenteritis (inflammation of the intestines and stomach).¹ It commonly causes diarrhoea and vomiting. But you may also feel nauseous and have stomach pain and fever. These symptoms usually appear 12-48 hours after being exposed to the virus so symptoms do have a rapid onset. With rest and over-the-counter medication it usually resolves on its own within a few days. 

How is it spread?

It is most commonly spread directly from one person to the next in the following ways:

• Contaminated water or food
• Contaminated surfaces
• Airborne particles from vomit
• Direct contact with infected people

Weakened immune system

The immune system is made of cells, organs and tissue which all work together to protect the body from germs and harmful substances.² If the immune system is weak and does not function properly, then the body will not be able to fight off infections and diseases. When something foreign enters the body it activates the immune cells and stores information so that if it ever enters the body again the body can recognise it and destroy it faster. 

Who has a weakened immune system?

People with the following are some groups that are considered as being immunosuppressed:

• People with HIV/AIDS
• Elderly
• Young children
• Those with a chronic disease
• Cancer patients
• Individuals who have received an organ from a donor as a transplant
• Individuals who have an autoimmune disorder
• Anyone taking medication that suppresses immune function

What are the effects of a weakened immune system?

Healthy people who have norovirus usually recover in a few days but those who have a weakened immune system can have symptoms that last for several weeks and maybe even months.³ The body finds it much harder to fight the virus. This causes:

• Longer periods of diarrhoea and vomiting 
• Slower time till recovery
• Increased chance of weight loss
• Greater risk of dehydration
• Prolonged feelings of weakness

Serious effects

Dehydration

This is a severe complication that can arise if norovirus is caught in someone who is weaker. It is caused due to:

• Constant vomiting and diarrhoea
• Being unable to keep fluids down
• For elderly patients - they can be less aware of their own thirst and drink very little amounts
• Some people with a weakened immune system have poor kidney function and are at  greater risk of becoming dehydrated

Warning signs of dehydration include:

• Darker coloured urine
• Excessive thirst
• Dry throat and mouth
• Feeling dizzy
• Dark, droopy eyes
• In severe cases, there may be confusion 

Malnutrition

The extended recovery time and being infected with norovirus for a long duration can cause:

• Fewer nutrients and deficiencies
• Increased weight loss
• Weakened muscles
• Slower healing
• More likely to get other infections

Chronic infection

Due to the weakened immune system:

• They may have norovirus for months
• They may have recurring symptoms that go and come back
• They carry the virus chronically 
• They may not be able to clear the infection fully

How to prevent norovirus⁴ 

Hand hygiene

• Wash hands often with water and soap for at least 20/30 seconds
• If there is no soap, use hand sanitiser which is less effective
• Clean hands before eating/touching food
• Wash hands after using the toilet

Food Safety

• Wash fruits and vegetables properly
• Always make sure shellfish is cooked completely and not raw
• Stay away from undercooked and raw food
• Clean surfaces before handling food
• Do not cook for others if you have the virus 

Environmental Considerations

• Clean surfaces that are regularly touched
• Use cleaning solutions that have bleach as it is more effective against the virus compared to common/standard products
• Keep your distance from anyone who is infected
• Take extra caution in riskier settings like hospitals

Further Protective Measures

• Wear masks in high-risk environments such as healthcare places
• If possible, use separate bathrooms from anyone who is infected at home
• Stay away from busy/crowded places when there is an outbreak of norovirus
• Take extra precautions when caring for infected people close to you, e.g. maybe wear gloves

When is medical intervention required?

If you have a weakened immune system and have norovirus, you should immediately contact your GP/111 if you have any of the following:

• Being unable to keep fluids down for 24 hours
• Diarrhea that lasts more than three days
• Excruciating abdominal pain
• Signs of dehydration
• Blood present in vomit or stool 
• Fever and temperature over 38.6 degrees
• Severe dizziness/weakness/fatigue

Treatment

There is no cure for norovirus, rather symptoms are managed by focusing on the below⁵:

Managing symptoms

• Take anti-nausea medication to stop/reduce the frequency of vomiting 
• Pain relief medication for any headaches or body pain 
• Anti-diarrhoea medication 
• Take extra fluids

Preventing dehydration 

• Taking regular fluids throughout the day
• Rehydration solutions 
• If at risk of dehydration, you may need an IV fluid
• Continuously look at urine output and colour to detect any changes 

Nutritional support

• Slowly, increase the amount you are eating
• Start with foods that are easier to eat and contain less spice
• May need nutritional supplements

Summary

Norovirus is generally unpleasant and causes discomfort for anyone who is seen as healthy, but it can be significantly worse for those who have a weakened immune system. The horrible, displeasing feeling that is usually felt for a few days can drag on and last much longer. This is why it is very important to understand what the risks maybe if you have a weak immune system and catch something like norovirus. Due to this, it is crucial you take the necessary precautions mentioned above, as this will significantly reduce the risk of getting ill with the virus. Medical care is not usually necessary, as home remedies, over-the-counter medication, and time are generally enough to act as a treatment. However, if symptoms do get worse and there are warning signs, it is important to go and get medical care, as such individuals are already immunocompromised.

If the right prevention techniques are taken seriously and you address symptoms as they are, the impact and any complications of norovirus can be greatly reduced. Prevention is always better than treatment, especially for those with compromised immune systems. Stay informed about local norovirus outbreaks, maintain strict hygiene practices, and don't hesitate to contact healthcare providers with concerns.

FAQs

What are the first signs of norovirus?

Symptoms are sudden and usually involve vomiting and diarrhoea. 

What food is norovirus found in?

It is usually found in shellfish like clams and oysters. It’s most commonly linked to oysters, as this is eaten raw.

Is norovirus the same as food poisoning?

It is more commonly known as the winter bug or stomach bug, but it is also referred to as food poisoning as the virus can be caught from contaminated food.

Can norovirus live in bedding?

It can live on surfaces, including bedding, for up to 4 weeks.

What is the best thing to drink after norovirus?

Take regular small sips of fluids like coconut water, iced tea, and anything that is high in sodium, potassium, and chloride. These are things lost in diarrhoea so need to be replaced.

What month is norovirus most common?

It is most common during the months from November to April.