Ask the experts: Long-haul COVID
While many people who contract COVID-19 recover within weeks, others experience persistent symptoms that can cause a range of adverse physical and psychological health effects for six months or more after initial recovery.
A November study estimated that at least 50% of survivors will become “long haulers” with residual health issues associated with COVID-19.
Common symptoms of long COVID include fatigue, shortness of breath or difficulty breathing, cough, chest tightness or pain, memory or concentration problems, trouble with sleep, joint or muscle pain, headache, heart palpitations, loss of smell or taste, depression or anxiety, fever, dizziness, and worsened symptoms after physical or mental activities.
Severe illness is not a prerequisite for long COVID —it also affects individuals who had mild cases — but research shows that individuals who did have more severe COVID cases and required hospitalization were more likely to experience longer-lasting cognitive dysfunction.
Children who are asymptomatic or have mild cases of the virus can also develop long COVID.
What short- and long-term health effects are associated with COVID-19, and how often do they occur? Are certain people more at risk?
Does being fully vaccinated offer more protection? What do we know so far about omicron – the most transmissible variant yet – and long COVID?
These answers have been edited for length and clarity.
What is long COVID?
There are several different definitions of “long” COVID, “long-haul” COVID or what we call post-acute sequelae of SARS-CoV-2 (PASC) out there. The simplest way to think about it is someone who continues to have symptoms after a COVID diagnosis, but how long someone is required to have symptoms varies between the different definitions.
The CDC defines post-COVID conditions as sort of four or more weeks after you’re first infected with SARS-CoV-2. As far as persistent symptoms, the more formal definitions of PASC require people to have symptoms for 12 weeks or about three months.
What are the symptoms of long COVID?
We see a variety of symptoms. The most common by far is fatigue. The second most common are often neurologic conditions. We see what's called brain fog or neurocognitive challenges, and headaches are very common. We also see lung conditions like shortness of breath or pain when you breathe in. We see heart challenges, we see it affecting people's kidneys, people's GI tract, people's livers, neuropathies. There are many, many ways that this can manifest, which is why there is not yet one clear definition of what this is.
Is loss of smell from COVID connected to the brain?
There are three conditions where loss of smell is prominent. One is after a head injury and the other two are Parkinson's disease and Alzheimer's disease. For many years, neurologists have considered using smell tests as early markers of neurodegenerative processes. So that was one cause for concern, but it does seem like the virus affects the brain in many ways. So if you do have anosmia or if you do have problems with smell and taste, there's a suspicion that you may be a little more likely to have long term COVID, but you don't have to have that to have neurological manifestations of long COVID.
What is brain fog?
Brain fog that is the sensation of a cognition not quite being what it was. And when you test, people fit the definition of what is called mild cognitive impairment, there may be slowness in thinking difficulty with memory.
- Dr. Barbara Taylor, MD, MS, associate professor of infectious diseases and assistant dean for the M.D./MPH program at UT Health San Antonio
- Dr. Sudha Seshadri, MD, professor of neurology and founding director of the Glenn Biggs Institute for Alzheimer’s and Neurodegenerative Diseases at UT Health San Antonio
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*This interview was recorded on Thursday, January 13.