Cerebral (brain) atrophy refers to a loss of brain tissues, including neurons and the connections between them. “Brain shrinkage” also falls under the umbrella of brain atrophy. It can apply to the entire brain or certain sections only.

Causes of brain shrinkage include:

  • traumatic brain injuries
  • stroke
  • degenerative brain diseases, such as dementia
  • infectious diseases that cause significant inflammation, such as AIDS and encephalitis

Research is ongoing to see whether COVID-19 is an infectious disease that can cause your brain to shrink.

In this article, we’ll review what studies have revealed so far about COVID-19’s effects on the brain.

For reasons not yet understood, some people who develop a COVID-19 infection may experience symptoms for several weeks, months, or years after recovery.

These post-COVID conditions are commonly known as “long COVID.” It occurs in people who’ve recently had COVID-19 and experience new, recurring, or ongoing symptoms 4 weeks or longer after the initial onset of infection.

Brain shrinkage is one such condition that may arise from long COVID. It has been garnering attention among researchers.

For example, one 2022 study used two magnetic resonance imaging (MRI) brain scans in 785 participants. Researchers found brain changes in the 401 cases who tested positive for COVID-19 between each scan. Changes included:

  • reduced gray matter (the outer layer of the brain)
  • tissue damage in areas of the brain connected to smell
  • decreased brain size

The study also found that the same participants who showed brain shrinkage were at a greater risk of experiencing cognitive decline. There was more tissue damage in the areas of the brain that control smell.

Possible explanations for brain shrinkage related to COVID-19 infection include inflammation or direct viral infection of the brain cells. But it’s important to note that most of the data were from before COVID-19 vaccines were available.

Another study also used MRI techniques to evaluate the brains of those who experienced COVID-19 infection. Here, researchers found damage to the small blood vessels in the brain.

Due to the small size of the study and other limitations, researchers couldn’t make definite conclusions about how COVID-19 affects the brain.

Many studies have linked COVID-19 to blood clots. This link may relate to damage to the blood vessels in the brain. The potential for blood clots in your brain also raises your risk of stroke after COVID-19 infection.

Other research has found that proteins on the SARS-CoV-2 virus may be toxic to the neurons in your brain.

One 2022 study also noted brain injuries in patients who died from complications related to COVID-19 during the first wave of the pandemic (March to July 2020). Researchers found evidence of protein leaks and neuron damage while conducting brain autopsies.

They also suggested that clinicians pay more attention to brain changes in people who survive COVID-19 infection and complain of cognitive symptoms that could be signs of long COVID.

Research summary

  • Brain images of people with a previous COVID-19 infection show a loss of brain matter in certain areas.
  • Autopsies of people who have died from COVID-19 show signs of brain damage.
  • Damage to your brain from COVID-19 may be due to inflammation, direct infection, blood clots, or neurotoxicity.
  • More research is needed to confirm COVID-19’s long-term effects on the brain.

The effects of COVID-19 on the brain may cause the following symptoms:

Your outlook for brain atrophy depends on the underlying cause. For example, dementias such as Alzheimer’s disease tend to get worse over time. In some cases, serious illnesses and diseases of the brain may affect your quality of life and even shorten your lifespan.

But experts don’t yet know if the brain effects from COVID-19, including brain shrinkage, are permanent.

Some research points to improvements in brain function within 6 months after COVID-19 infection. But more studies are needed to determine whether this is a typical outcome.

The best way to prevent COVID-19 infection is to get vaccinated. It’s also best to keep up with your recommended vaccination schedule.

According to the Centers for Disease Control and Prevention (CDC), getting the vaccine can also help protect you against long COVID and its effects, including brain shrinkage. Serious illness from COVID-19 infection is a risk factor for developing post-COVID conditions. Vaccinated people have a lower risk of serious illness from the virus.

The CDC also notes that it’s still possible to develop long COVID even if you get the vaccine or don’t get severely ill. Still, vaccination appears to be the best way to prevent the effects of long COVID.

Aside from protecting yourself against COVID-19 infection, you can adopt brain-healthy strategies that may help prevent atrophy more generally. Experts suggest that you:

  • Eat a healthy diet.
  • Manage your blood pressure.
  • Exercise regularly.
  • Stay socially active.
  • Adopt new hobbies and activities.
  • Keep doing hobbies and activities that you enjoy.

How can people who are not vaccinated prevent long COVID and its effects on the brain?

Vaccination is the best way to safeguard against long COVID. But if you’re not vaccinated and develop a COVID-19 infection, you’ll need to wait until after you recover before you can get the vaccine. Until then, you should try to reduce your risk of serious illness.

Try to get plenty of rest. Talk with a doctor about your infection so that you can get the medical care you need. Seek medical attention if you start feeling shortness of breath or have other concerning symptoms.

Brain shrinkage, which is related to brain atrophy, is a possible long-term effect of COVID-19 infection. Researchers are continuing to explore the effects of COVID-19 on the brain.

If you have a COVID-19 infection, it doesn’t mean that you’ll experience brain effects. Still, protecting yourself against the SARS-CoV-2 virus may help prevent such long-term effects. Vaccination is the best way to prevent an infection.

Right now, there’s no test to identify long COVID. But if you’re experiencing cognitive symptoms 4 weeks after your initial COVID-19 infection, consider talking with a doctor to discuss treatment and management options.