Long COVID is a colloquial term used to describe the lingering health symptoms some patients experience after contracting the COVID-19 virus. While the majority of people fully recover from the virus, some “long-hauler” patients report long COVID symptoms ranging from general fatigue to headaches and brain fog, also known as post-COVID cognitive dysfunction. Study of the long-term neurological effects of COVID-19 is a new area of research for neurologists and immunopathologists, and while there are still many unknowns, recent studies have uncovered promising potential biomarkers and diagnostic challenges to consider in the development of new clinical trials.
In our latest long COVID webinar held on April 26, three specialists gave a comprehensive presentation on the latest pathophysiology learnings of post-COVID neurological symptoms. Below, discover some of the biggest takeaways on long COVID from our experts. For a deeper dive of COVID-19 neurological effects, watch the webinar recording.
Q: What are some common symptoms of COVID-19 long-haulers?
Dr. Peluso: Symptoms can really be different between different individuals; there’s no one long COVID phenotype. And in addition, symptoms can vary over time within a single individual. There are neurologic symptoms like headaches and brain fog, and cardiopulmonary symptoms, like heart palpitations, chest pain and dysautonomia in some individuals. Mental health symptoms like depression or anxiety, and more generalized symptoms like fatigue and muscle aches (have also been reported).
Dr. Lambert: Thanks to so many long-haulers taking surveys, we’ve been able to learn about these different cognitive impacts and include them in future studies. We found that fatigue was the most common symptom, followed by high headache, shortness of breath and difficulty concentrating. We then found that a quarter of survey takers reported 31 or more symptoms. So this was a good reminder to all long COVID researchers that we need to take a more open-ended approach (to studies).
Q: What’s the pathophysiology that might underlie persistent neurocognitive symptoms in long COVID?
Dr. Peluso: Many people who have acute COVID will recover fully, but a subset will go on to develop long COVID. So there is some early compelling evidence that a subset of individuals may exhibit persistent virus. This doesn’t mean that there is infectious virus that’s persisting in a person’s body, but it does mean that there are potentially viral antigens, a protein or genetic material that could be stimulating an immune response, which can lead to something like inflammation.
Q: How does COVID-19 affect the brain?
Dr. Peluso: A really important study came out (recently). This study included about 500 individuals who are participating in a serial brain imaging study with MRIs. All of these individuals had pre-COVID MRIs, and then (researchers) looked at a group of people who developed COVID and a group that did not have COVID. They found that people who recovered from COVID had measurable structural changes on MRI over time, including a decline in the thickness of their gray matter, tissue damage along the olfactory tracts and a decrease in their overall brain size.
Professor Maruff: The types of cognition and psychiatric symptoms that remain generally progress over long periods of time. Here the data is clear in the differences in what are called neuropsychiatric cognitive symptoms, reported as brain fog, memory issues, slurring words and speech and language issues. So people are reporting qualitatively quite specific aspects of their thinking that are disrupted right throughout the course of COVID.
Q: What are the key takeaways for long COVID-19 researchers planning their next clinical study?
Dr. Lambert: A common aspect of the long-hauler experience is that there’s not an even trajectory towards long COVID recovery. It’s often that people will feel a little bit better—maybe some of their cognitive symptoms will seem to lessen or go away for a bit. But then they find that especially with a lot of physical activity, or even having to focus more at work, that these symptoms can come back. Measuring long COVID at one point in time is not going to capture the full picture. And we need to realize that when we’re creating therapies or solutions for people. We have to be flexible in our diagnosis methods until we know more. Collaboration with patients and patient groups is essential for doing meaningful long COVID research, even to make sure we’re asking the right questions, studying the things that patients want us to study so they can get relief.
Have more questions on the long-term neurological effects of COVID-19? See the full webinar recording in our Knowledge Library.