Here’s What COVID Brain Fog Feels Like — And What To Do About It

“It seems so silly that you couldn’t automatically think of what you wanted immediately.”

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A woman in a foggy forest. Here's what COVID brain fog feels like and what a possible cause might be...
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When Jessica*, 32, got COVID in November, the self-employed stylist and designer felt lucky that she could take time away from work to recover. Though she was back on her feet within two weeks of first testing positive, she’s still dealing with one major COVID symptom, three months later: brain fog.

Along with fatigue, brain fog is the most common symptom reported by COVID long haulers, or people whose COVID symptoms last more than a month after first getting sick. Brain fog is a non-scientific term that includes a range of neurological symptoms, from poor word recall to trouble concentrating to just generally “fuzzy” thinking. It can occur with viral illnesses like COVID, per Harvard Health, or conditions like hypothyroidism or sleep apnea. A pre-publication study that came out in December 2020 found that around 55% of COVID patients reported having brain fog for at least six months after first contracting COVID, among other neurological symptoms.

Jessica describes her brain fog as “just having to think harder about what you want to say instead of automatically knowing. Like the word or description that you want is on the tip of your tongue, and you’re trying to remember what exactly it is — and it seems so silly that you couldn’t automatically think of what you wanted immediately.” She particularly has trouble with speech: “I’ve found that I’ve started to stammer my first word [in a sentence] sometimes, which I’ve never done before in my entire life,” she says.

What Causes COVID Brain Fog?

Generally, when an illness leads to brain fog, it’s thought that the virus is getting into the brain and triggering an inflammatory response, explains Dr. David Nauen, M.D., PhD, a neuropathologist at Johns Hopkins University. “This immune response can cause damage to the brain tissue,” causing brain fog.

But researchers have been puzzled by COVID brain fog in that they hadn’t been able to find visible inflammation in brain tissue samples from people who died of COVID. A study published in February, spearheaded by Dr. Nauen, suggests that some unusual cellular movements might explain why COVID patients get brain fog.

After examining samples, the research team found unusual cells present in the capillaries, or the vessels that bring oxygen to the brain. Nauen realized that these cells looked a lot like large, megakaryocytes that normally live in bone marrow, and wouldn’t be present in a blood vessel. “It looked like if you took a small pipe and then stuffed a football in there,” says Nauen. “You could see how water wouldn’t flow through a pipe in that situation.”

“By altering how blood can flow through the capillaries, this could alter how the brain gets oxygen, which might alter someone’s thinking,” says Nauen, adding that more research needs to be done to understand why these cells are going to the brain, and how long it’ll take that to subside. “We don’t know enough yet to know why these neurological symptoms like brain fog persist after someone’s recovered from the acute phase of their illness, but it’s possible these platelets in the capillaries are contributing to this.”

How To Help COVID Brain Fog

For those left reckoning with COVID-related brain fog, the question of how to cope until science catches up with answers remains. Amanda, 28, has dealt with tremendous fatigue and brain fog since having COVID in the spring and early summer. She found it helpful to do crosswords and other word puzzles with her non-dominant hand, a brain and memory exercise often recommended for seniors. If it was good enough for someone in memory care, she figured it would be good enough for her, and sure enough, she says she bounced back in about a month.

Where Jessica used to “wing” work assignments easily, as a bonus of working in a creative field, she now relies heavily on keeping notes from brainstorms and rewriting highlights, “so that everything is fresh and right in front of me before I revisit a project.” She adds, “The creativity process tends to flow when I’m not put on the spot during a meeting.”

For dealing with brain fog outside of work contexts, she says that a newfound meditation practice has helped more than anything. Given that meditation is thought to help exercise the prefrontal cortex of the brain, this isn’t surprising. “Whether using breathing patterns or guided meditation or even just putting on calming music, mindfulness really helps me to recharge, reground, and recenter.”

If post-COVID brain fog is affecting your ability to take care of things day-to-day, talk to your doctor about whether these or other techniques can help.


Dr. David Nauen, M.D., PhD

Studies cited:

Nauen DW, Hooper JE, Stewart CM, Solomon IH. Assessing Brain Capillaries in Coronavirus Disease 2019. JAMA Neurol. Published online February 12, 2021. doi:10.1001/jamaneurol.2021.0225

Characterizing Long COVID in an International Cohort: 7 Months of Symptoms and Their ImpactHannah E. Davis, Gina S. Assaf, Lisa McCorkell, Hannah Wei, Ryan J. Low, Yochai Re’em, Signe Redfield, Jared P. Austin, Athena AkramimedRxiv 2020.12.24.20248802; doi:

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