Long COVID can actually rewire your brain, according to a new study

Long COVID can change the brain of people who suffer from it compared to those who recover from the virus, a new study has found.

To find these results, scientists from Germany compared MRI scans of three groups, including 89 patients with long COVID, 38 who recovered from COVID, and 46 with no history of COVID.

It found that the COVID-19 infection induced a "specific pattern" of microstructural changes in various brain regions, and the pattern differed between those who had long COVID and those who did not.

These revealed a correlation between the microstructural changes and symptom-specific brain networks associated with impaired cognition, sense of smell and fatigue.

"To the best of our knowledge, this is the first study comparing patients with long COVID to both a group without history of COVID-19 and a group that went through a COVID-19 infection but is subjectively unimpaired," study author, Doctor Alexander Rau, of University Hospital Freiburg, said.

Researchers added that it remained "unclear" as to why some people develop long COVID while others do not.

It comes after reports from earlier this year found that tens of thousands of people in England may have lasting symptoms of COVID for more than a year after infection, with researchers also revealing which are most commonly experienced.

The analysis – based on more than a quarter of a million people who self-reported their symptoms as part of the REACT study – found that while the vast majority recovered from infection within two weeks, a significant proportion (7.5%) endured persistent symptoms for 12 weeks or more.

Overall, the average duration of symptomatic illness was around 10 days long. However, one in 10 people reported symptoms for more than four weeks, one in 13 for more than 12, and one in 20 (5%) for more than a year. Meanwhile, researchers found the most common lasting symptoms were mild fatigue, difficulty thinking or concentrating and joint pains, though there are many more to be aware of.

A study from September also suggested that the brain fog often experienced by people living with long COVID could stem from blood clots. While many who get a positive test for coronavirus can recover within a few days, not everyone who overcomes the virus returns to a clean bill of health, with many thought to be suffering from ongoing impacts (from weeks to even years in some cases).

Despite supposedly clearing the virus from their body, sufferers are thought to experience everything from fatigue to organ damage, but some people with the condition experience problems with blood flow and lung capacity, which have been linked to tiny, abnormal blood clots.

The research, published in the journal Nature Medicine, suggests blood clots could also drive the neurological symptoms of long COVID, such as brain fog, which can impact memory and the ability to focus and execute tasks.

However, the study authors weren't able to fully establish how the clots might actually damage nerves or the brain to trigger brain fog.

Lead study author Dr Maxine Taquet, a clinical psychiatrist at the University of Oxford, told Live Science that fibrinogen-related blood clots may be derailing blood flow to the brain or perhaps directly interacting with nerve cells.

How common is long COVID?

According to the World Health Organisation (WHO), studies show that around 10 to 20% of people who get COVID may go on to develop long COVID symptoms, and up to 17 million people across the WHO European Region experienced long Covid in 2020 and 2021.

A February 2023 report from the Office for National Statistics (ONS) found that an estimated two million people, or 3.1% of the British population, are experiencing self-reported long COVID symptoms as of 2 January 2023

What is long COVID?

While long COVID, or post COVID-19 syndrome, is a new condition that is still being studied, it is thought to be triggered by the COVID-19 infection.

WHO defines long COVID as the "continuation or development of new symptoms three months after the initial SARS-CoV-2 (COVID-19) infection, with these symptoms lasting for at least two months with no other explanation".

Long COVID causes

Anyone who experiences the virus is at risk of developing long COVID, but a 2023 study of 800,000 people by Harvard University found that those with pre-existing health conditions such as high blood pressure, chronic lung disease, obesity and diabetes were more likely to develop long COVID.

While the cause is still being studied, a small-scale study from the University of Utah recently pinpointed a particular set of proteins in the body that control growth and the activity of immune system cells that were "almost undetectable among individuals who had long COVID".

This caused researchers to suspect that, for some people who get COVID, their lungs and other organs are unable to fully heal which can leave them more susceptible to other illnesses.

Who is most likely to experience long COVID?

The ONS report found that long COVID is more common in:

• people aged 35 to 69

• women

• people living in more deprived areas

• social care workers

• those with an activity-limiting health condition or disability

Long COVID symptoms

According to the NHS, the most common symptoms of long COVID are:

• Fatigue (extreme tiredness)

• Shortness of breath

• Loss of smell

• Muscle aches

Other common long COVID symptoms include:

• Brain fog (memory and concentration issues)

• Chest pain and tightness

• Insomnia and difficulty sleeping

• Heart palpitations

• Dizziness

• Pins and needles

• Joint pain

• Anxiety and depression

• Earaches and tinnitus (ringing of the ears)

• Nausea, diarrhoea, stomach aches, loss of appetite

• High temperature, cough, headaches, sore throat, changes to taste and smell

• Rashes

Looking at the Imperial College London study specifically, aside from mild fatigue, difficulty thinking or concentrating and joint pains being the three most common, other persistent symptoms reported included loss or change of sense of smell or taste, shortness of breath, severe fatigue, chest tightness or pain, and poor memory.

The research found people were more likely to report symptoms for a long time after their initial infection if they were female, had severe initial symptoms, were infected earlier in the pandemic, or had pre-existing health conditions. Meanwhile, some of these symptoms were quite often reported by people who did not have previous COVID.

While findings from the analysis – published in Nature Communications – show that a significant proportion of adults experience long COVID, which in some cases lasts a year or more, the researchers also highlight that a sizeable proportion still fully recover after a prolonged period.

WHO says the most common symptoms of long COVID include "fatigue, shortness of breath and cognitive dysfunction", and adds that the condition can have over 200 different symptoms.

An ONS report found that fatigue was the most commonly reported symptom for long COVID patients (71%), followed by difficulty concentrating (52%), shortness of breath (48%) and muscle aches (47%).

Read more: Long COVID

• Three types of long Covid each with different symptoms, researchers say (Sky News, 2-min read)

• Long Covid patient opens up about his mental health (Yahoo Life UK, 1-min read)

• Here's why you feel breathless when you have long Covid (Yahoo News UK, 2-min read)

Watch: Long COVID smell loss 'linked to changes in the brain'

Long Covid treatment

If you suspect you have long COVID, you can speak to your GP about managing your symptoms and possible tests to rule out other things that could be causing them.

If your symptoms are having a big impact on your life, your GP may refer you to a specialist service that could help you recover.

A healthcare professional can refer you to the NHS’s Your COVID Recovery programme, an online recovery programme that can offer support and ways to manage symptoms.