Several studies have shown that RSV (Respiratory Syncytial Virus) – a very common respiratory virus – can sometimes lead to neurological complications in children and teenagers, i.e. problems affecting the brain. In this article, we explore what RSV is, and why and how it may cause neurological issues. 

What is RSV?

RSV, which stands for Respiratory Syncytial Virus, is a common respiratory virus – a virus which affects your breathing system – and is usually the cause of a cough or a cold. By the age of 2 years old, it is very unlikely that a child will not have caught it at least once, and most of us continue to catch it at different times throughout our lives. As it is usually not serious, this is normally not a cause for concern, although you may experience some unpleasant symptoms a few days after infection.

Symptoms

Symptoms of RSV can include:

• Blocked nose 
• Running nose
• Coughing 
• Sneezing 
• Fatigue 
• Fever 

Can RSV become serious? 

Whilst it is mild in the majority of cases, for more vulnerable people such as babies < 6 months old, elderly people 75+ years old, or those with conditions which make their immune system weak, RSV can cause more serious infections. The most common example of this is bronchiolitis (not to be confused with bronchitis) in children and babies < 2 years old, and pneumonia.

Neurological complications of RSV

Although these more serious infections caused by RSV are infections of the lungs and airways, research has shown that for some, these infections could affect the brain too, causing neurological complications.

Who can be affected by the neurological complications of RSV?

There is an almost complete lack of evidence to demonstrate that adults develop neurological complications from RSV.¹

However, various studies have found it to be possible among children and teenagers up to around the age of 14 or 15 years old. So, how common is it for children and teens to develop these complications following an RSV infection? 

Are neurological complications of RSV in children and teens common?

In a study of 964 patients under the age of 14 who had been hospitalised for RSV bronchiolitis, experts found that:

• Twelve of these patients who tested positive for the virus had neurological complications with no other recognised cause
• Seven of them were seizures
• Three of them had generalised encephalopathy (damage or disease of the brain)
• Two of these three had developed esotropia – an eye condition when 1 or both of your eyes point inwards

Overall, excluding pre-existing conditions or simple febrile seizures (when a child has a seizure due to a fever), 1.2% of these patients had neurological complications associated with RSV bronchiolitis.²

Research like this proves that it is possible to develop complications affecting the brain from RSV infections, however, it is very uncommon. 

What are the possible neurological complications of RSV?

When Saravnos et al reviewed studies like the one mentioned above to examine how the brain can be affected by RSV in children and teenagers, they found the following to be the most common neurological complications: 

• Seizures – when your brain cells stop functioning properly and send unstoppable electric signals. This can cause people to lose consciousness or have uncontrollable muscle movements
• Encephalopathy – This refers to many different types of diseases or disorders in the brain, which can include changes in personality, loss of memory and confusion
• A decreased level of consciousness – this can refer to being less alert or aware of one’s surroundings or struggling to understand things³

Their review also found that there were other cases of neurological complications from RSV infections such as: 

• Fulminant cerebral oedema – a neurological condition that is still not well understood, but is very dangerous and debilitating.⁴ It is a newly recognised type of encephalitis (inflammation of the brain)⁵
• Infarction – also called a stroke. This is when the brain becomes damaged due to a lack of blood flow and therefore oxygen
• Meningitis/encephalitis – Meningitis is an infection of the protective membranes around the brain/spinal cord and can cause sepsis. Encephalitis is inflammation of the brain. Both can be life-threatening
• Paralysis – the inability to move parts or all of your body

These complications were found to be much more rare and are more severe. 

How can RSV cause neurological complications? 

Experts are still not 100% clear on how RSV causes neurological complications like those listed above. There are, however, other infections which are known to cause serious conditions of the brain such as:

• Enterovirus-D68 causes acute flaccid myelitis – a condition which weakens your reflexes and muscles⁶
• Enterovirus-A71 causes encephalitis – inflammation of the brain⁷
• Coronavirus causing demyelinating disease – damage to the protective covering of your nerve cells⁸

These cases are rare, but it does tell us that viral infections can have an impact on our brain without necessarily doing so to everybody who catches them. 

This has led experts to question how RSV is causing these neurological complications. A recent study has helped shed light on this, by confirming that RSV is able to enter the spinal cord, with it being detected in the cerebral spinal fluid (the liquid surrounding the brain/spinal cord) of several patients. 

The spinal cord is part of your central nervous system which connects your brain to the rest of your body and allows it to send out signals. It was revealed in this study that RSV is able to enter the spinal cord through the peripheral nerves (the nerves outside of the brain and spinal cord).

More research is needed to be sure, but there is a theory from this that once in the spinal cord, RSV can get around the blood-brain barrier (which stops harmful things from getting to the brain) to enter the central nervous system and therefore infect the brain.⁹

If the brain can be infected by RSV, it would explain how these neurological complications are caused by certain RSV patients. 

How can neurological complications of RSV be prevented?

Unfortunately, there is no proven way to prevent these complications from happening. There is still a long way to go in the research field of how RSV and certain brain conditions are linked. 

However, doing all you can to prevent catching RSV or to prevent it from becoming more serious is the best way to protect yourself. It is spread through people coughing or sneezing when they are infected with the virus. So, according to the NHS, the following measures can help to reduce the spread:

• Make sure you and your children are washing your hands regularly 
• Clean surfaces in your home and workplace regularly 
• Do not share cutlery/drink containers 
• Use tissues when you cough and sneeze, and dispose of them afterwards 
• Be sure to keep newborn babies away from anyone who has a cold or flu 

It is also important if you are vulnerable to RSV infections that you get vaccinated to decrease the risk it poses to you. As of the 1st September 2024, the NHS will be offering vaccines against RSV to:

• Expectant mothers (28+ weeks pregnant)
• People between the ages of 75-79 years old

If you are pregnant, you should contact your GP to organise your vaccination. If you are aged 75-79, you will be contacted. 

Call the emergency services for somebody with RSV if

• They are having serious problems breathing
• You cannot wake them up, or they will not stay awake 
• They are younger than 5 years old and have a temperature below 36 °C
• Their lips are pale/blue/grey

Summary 

RSV is a common infection which usually causes a cold or flu and It is usually mild and not a cause for concernStudies have found that it can cause neurological complications for children and teenagers which include seizures, brain disorders/diseases, and a change to their level of consciousness, even if in rare occasions. These complications occur when RSV enter the spinal cord and infects the brain. More research is needed to evaluate a possible association between RSV and neurological complications. You cannot directly prevent these complications but you can help prevent the spread of RSV. Pregnant women (28+ weeks) and people aged 75-79 years old can have a vaccine on the NHS from September 2024. Call 999 if somebody with RSV shows severe symptoms.