We know there is a lot of variation in how COVID affects people. Some feel like they have a bit of a cold, some feel like they have the flu, and some end up in the hospital. No matter the symptoms, we tend to think that people get sick, they get better and recover, then move on. Most of the time, that's what happens, but for about 10% of people who get COVID, the experience is different.
Long COVID is defined as ongoing symptoms for more than 12 weeks after the initial infection. Exactly what those symptoms are varies. There's currently a list of over 200 possible symptoms - but most people have the 3 most common. Those are: extreme fatigue, post-exertional symptom exacerbation, and problems with memory or concentration - commonly referred to as "brain fog."
The extreme fatigue associated with Long COVID affects the ability to complete daily tasks. It causes severe tiredness that you can't get rid of with rest or sleep. It's also not related to doing some physically demanding task.
Post-exertional symptom exacerbation, or PESE is a disabling and often delayed exhaustion disproportionate to the effort made. Patients are referring to this as a "crash". The activity that brings on the crash is something that was easily tolerated before the COVID-19 infection. Some examples would be taking a shower, walking, attending a social activity, or even being in a high sensory environment with flashing lights and loud noises.
"Brain fog" isn't a medical condition. Instead, it's a term used by patients to describe thinking that is sluggish or fuzzy. In severe cases, people describe it as feeling like their brain shuts down. They could be in the middle of a sentence and not be able to think of anything more to say. They could be at work doing a task they've done a thousand times and be unable to think of the next step. Just like the extreme fatigue and PESE we've already described, the brain fog associated with Long COVID is disabling and affects every aspect of daily life.
We're still learning exactly what causes Long COVID and how best to manage it. What we do know is that Long COVID has an ongoing effect on patients. It touches every part of their lives. We also know that we need to learn more about this condition and how to help people who have it.