People with Covid-19 can experience brain fog, fatigue, and other side effects that last for several months. It is also known as Long Covid.

Although the cause of these symptoms is still unknown, new research could shed some light on the matter.

The virus is believed to spread rapidly from organs and tissues in the body, according to researchers at the US National Institutes of Health.

The researchers examined tissue samples taken from 44 coronavirus-infected patients during an autopsy.

There was evidence of the virus spreading beyond the respiratory system and it had been found in various organs including the heart and brain for as long as 230 days. 

‘Our results collectively show that while the highest burden of SARS-CoV-2 is in the airways and lung, the virus can disseminate early during infection and infect cells throughout the entire body, including widely throughout the brain,’ the team, led by Daniel Chertow wrote.

From brain fog to fatigue, many people with Covid-19 suffer from debilitating side effects for months after their infection, in a condition collectively referred to as long Covid (stock image)

People with Covid-19 can experience brain fog, fatigue, and other side effects that last for many months. It is also known as long Covid (stock illustration).

Long Covid symptoms 

Common long COVID symptoms include:

  • Extreme tiredness (fatigue).
  • Shortness of breath
  • Chest pains or tightness
  • Memory and concentration problems (“brain fog”)
  • Insomnia is a condition that causes difficulty in sleeping.
  • heart palpitations
  • dizziness
  • Pins and Needles
  • joint pain
  • Depression and anxiety
  • Tinnitus and earaches
  • Feeling sick, nausea, vomiting, stomach pains, and loss of appetite
  • High temperature, coughing, headaches and sore throat.
  • Rashes  

The NHS states that everyone is unique in how long they take to heal from COVID-19. 

Many people will feel much better within a couple of days, or even weeks. Most people recover fully in 12 weeks. It explained that some symptoms might last longer for others.

The likelihood that you will have long-term symptoms doesn’t seem to depend on how sick you were when you get COVID-19.

People who have mild symptoms may still experience long-term issues. 

While long Covid is estimated to affect as many as one in 20 people with Covid-19, the burden of infection outside the respiratory tract, and the time taken to clear the virus hasn’t been well studied.

Researchers at the NIH, Bethesda (Maryland) conducted extensive samples of tissue taken from autopsies performed on 44 patients.

They found persistent SARS CoV-2 in many organs up to 230 day after onset symptoms.

‘We show that SARS-CoV-2 is widely distributed, even among patients who died with asymptomatic to mild COVID-19, and that virus replication is present in multiple pulmonary and extrapulmonary tissues early in infection,’ the researchers wrote.

‘Further, we detected persistent SARS-CoV-2 RNA in multiple anatomic sites, including regions throughout the brain, for up to 230 days following symptom onset.’

In the new study, undertaken at the NIH in Bethesda, Maryland, the researchers carried out extensive sampling of tissues taken during autopsies on 44 patients. Their analysis revealed persistent SARS-CoV-2 in multiple organs, including the brain (scans pictured) for as long as 230 days following the onset of symptoms

Researchers at the NIH, Bethesda (Maryland) conducted a new study that included extensive collection of tissue taken from autopsies performed on 44 patients. They found persistent SARS-2-CoV-2 in many organs (scans shown pictured), for as much as 230 consecutive days following the onset symptoms.

Although the exact cause of this effect is still unknown, researchers believe that the non-respiratory system may be able to produce less effective immune responses against the virus.

‘This less efficient viral clearance in extrapulmonary tissues is perhaps related to a less robust innate and adaptive immune response outside the respiratory tract,’ they explained.

It’s important to note that the research is yet to be peer reviewed, and relates to fatal Covid cases, and not people currently living with long Covid.

However, scientists have called the findings ‘remarkably important.’

Speaking to Bloomberg, Ziyad Al-Aly, director of the clinical epidemiology centre at the Veterans Affairs St Louis Health Care System, who was not involved in the study, said: ‘This is remarkably important work.

‘For a long time now, we have been scratching our heads and asking why long Covid seems to affect so many organ systems.

‘This paper sheds some light, and may help explain why long Covid can occur even in people who had mild or asymptomatic acute disease.’ 


Covid-19 refers to a temporary illness that is caused by the SARS-CoV-2 virus. According to public health experts, people are likely to recover within two weeks. 

It’s becoming increasingly obvious that this may not be the case for all, and that two weeks is just the “acute illness” phase.

The North Bristol NHS Trust’s Discover project, which is studying the longer-term effects of coronavirus, found that out of a total of 110 patients given a three-month check up, most (74 per cent) had at least one persistent symptom after twelve weeks. These were the most frequent:

  • Excessesive fatigue 39%
  • Breathlessness: 39%
  • Insomnia: 24%  
  • Muscle pain: 23%
  • Chest pain: 13%
  • Cough: 12%
  • Loss in smell: 12%
  • Fever, headache, diarrhoea, and joint pain: All less than 10% 

Covid-19 survivors have reported hearing loss, brain fog, memory problems, concentration problems, mental problems and hair loss as long-term symptoms.

Long Covid’s effects on mildly ill people have yet to be studied.  

According to data from King’s College London, Covid-19 has been shown to have long-term side effects in up to half a million people across the UK.

In October, scientists claimed Long Covid could actually be split into four different syndromes.  

Academics at the National Institute for Health Research — headed up by Professor Chris Whitty — were asked to review the limited evidence on long Covid to help both patients and doctors understand the ‘phenomenon’. 

They found that Covid-19 can cause severe side effects in children, so it is not surprising that they are putting them at higher risk.

Some mental problems, such as depression and anxiety in long-haulers, were attributed to locking downs rather than the virus. 

According to experts, the symptoms could also be broken down into four distinct groups. 

  • Post intensive care syndrome (PICS)
  • Post viral fatigue syndrome (PVFS) 
  • Permanent organ damage (POD)  
  • Covid long term syndrome (LTCS).