COVID-19 is the disease caused by an infection with the novel coronavirus SARS-CoV-2. If you have COVID-19, you may experience a range of symptoms such as:

  • fever or chills
  • cough
  • sore throat
  • shortness of breath
  • headache
  • diarrhea
  • loss of taste or smell

For most people who get COVID-19, these symptoms go away with time, just like with any viral infection.

But there are notable differences between COVID-19 and other viral illnesses, like the flu, such as the potential for severe illnesses, death, and long-term effects among people who recover.

For some people, COVID-19 may cause long-term neurological (brain and nerve) effects, including brain fog. These brain effects may happen during your illness, as soon as you’ve recovered, or even many months after.

Studies are ongoing, but researchers believe brain fog may happen due to structural changes in the brain. In this article, we discuss this in detail and look at the research and findings.

Just like they affect the body, many kinds of illnesses can affect the brain. In some cases, the effects on the brain may be longer lasting than the illness itself.

Like other pandemics, COVID-19 may be linked to a higher likelihood of post-traumatic stress symptoms (PTSS) that can alter how the brain functions.

To test this theory, researchers in a 2021 study compared 173 people who had recovered from COVID-19 with a control group of 169 people who had not had COVID-19.

In two different sessions, the COVID-19 survivors scored significantly higher for post-traumatic stress disorder (PTSD) than the control group.

Brain scans showed structural and functional changes in the group who had recovered from COVID-19. These included changes in volume and activity in two areas of the brain linked to storing and recalling memories and expressing emotions: the hippocampus and the amygdala.

Researchers noted these findings highlight the importance of mental health care in people who have gone through COVID-19 and other traumatic illnesses.

Longer lasting symptoms experienced by people who have recovered from COVID-19 have been termed “long COVID” and “post-acute sequelae of SARS-CoV-2 infection (PASC).”

One of the most commonly reported long COVID effects is brain fog. Like other brain effects, brain fog can happen for several reasons, including lack of sleep, low blood sugar, and various illnesses and diseases.

COVID brain fog happens during or after a person gets COVID-19. It’s typically temporary but may last for some time in other cases.

In most cases, brain fog from COVID-19 gets better on its own, but doctors don’t yet know how long symptoms last on average.

Researchers do not yet know how common COVID brain fog is, either, but they estimate that up to 32 percent of people who have recovered from COVID-19 have brain fog and other brain effects as part of their long COVID symptoms.

Brain fog is described as slower or sluggish thinking and other changes to brain function or the ability to think. People with COVID brain fog describe a range of symptoms and may have difficulty with:

  • attention
  • focus
  • concentration
  • memory recall
  • ability to learn
  • planning
  • following instructions
  • multitasking

Long COVID–linked brain fog is often temporary and will improve on its own without treatment. We don’t know exactly what causes brain changes or symptoms in COVID, but experts believe inflammation may play a role.

According to a 2022 study, there’s no one way to treat or manage COVID brain fog. Instead, doctors might recommend several actions, including:

  • following a diet and lifestyle plan that helps calm inflammation
  • staying active with daily exercise, no matter how low intensity, to improve blood flow to the brain and body, and reduce brain inflammation
  • mental exercises, like puzzles, to stimulate thinking
  • being social and spending time with friends and family

Some supplements and medications may also help soothe or reduce inflammation.

Researchers in a 2021 lab study looked at a natural anti-inflammatory supplement found in olive pomace oil called luteolin. They found that luteolin may help the brain recover after long COVID and other causes of brain fog, including chemotherapy treatment.

However, this was only a chemical lab study. There have not been any human or animal studies to date. Be sure to check with your doctor before using any type of herb or oil supplement.

Researchers aren’t sure why some people who recover from COVID-19 experience brain fog and others do not. But a 2022 study suggests that some illnesses or factors may increase the chance of getting long COVID symptoms like brain fog.

These risk factors include:

  • previous psychological illnesses, such as major depressive disorder
  • PTSD
  • family history or early symptoms of Alzheimer’s disease or dementia
  • stroke or heart problems
  • moderate or high weight gain during or after having COVID-19
  • poor nutrition
  • lack of exercise
  • lack of social and mental stimulation

How common is brain damage from COVID-19?

Researchers don’t yet know how common changes to the brain from COVID-19 are. However, brain health clinics report that an average of 32 percent of people who recovered from COVID-19 have experienced brain fog.

Is brain damage from COVID-19 permanent?

In most cases, brain changes from COVID-19 are temporary and clear up on their own.

Can even mild COVID-19 symptoms lead to brain damage?

A 2021 review of studies found that brain fog and other brain effects can happen even after people experience mild COVID-19 symptoms. Researchers don’t know exactly why this happens or how common long COVID brain symptoms are after mild illness.

Is my loss of smell and taste from COVID-19 a result of brain damage?

The loss of smell and taste during and after having COVID-19 is a very common complaint. Researchers don’t yet know exactly why this happens.

The temporary loss of smell and taste can happen even in people who experience very mild nose symptoms from COVID-19, such as a blocked or runny nose.

For this reason, doctors believe loss of smell and taste may be due to inflammation or changes to the olfactory (smell) system in the brain. Research on this common COVID-19 symptom is ongoing.

If you’ve had COVID-19 and are now experiencing symptoms of long COVID, such as brain fog, you are not alone. Brain changes and lingering symptoms of COVID-19 are common. The research on why they happen is still ongoing.

Let a doctor know about any symptoms or changes you experience, even if they occur months after you’ve had COVID-19.

Ensure that you and your loved ones receive all the recommended doses of COVID-19 vaccination. Getting vaccinated can help protect you from COVID-19, prevent severe symptoms like brain effects, and reduce the risk of transmitting the infection to someone else.