By now, we’re getting a better understanding of what coronavirus disease looks like. We know COVID-19 can be a fairly mild flu-like illness for many people; some people don’t even know they have it. We also know that it can be deadly for others. It can have a range of serious health impacts, such as widespread blood clotting and strokes and, in some rare cases, cause an immune overreaction known as a cytokine storm.
COVID-19 long-term effects: People report ongoing fatigue, brain fog and breathlessness, so what’s happening in the body?
What’s less clear, however, are the longer-term health effects of COVID-19.
It’s worth remembering it’s been less than nine months since the first cases of what we now know as COVID-19 emerged in Wuhan, China, so its long-term health effects are still impossible to know.
But over the past few months, anecdotes have emerged of people experiencing strange, ongoing symptoms, including prolonged fatigue, breathlessness, brain fog and digestive issues.
As with many aspects of the new coronavirus, researchers are trying to pull together data to understand the medium-term health effects more fully.
COVID-19 “long-haulers”, as many of the people with prolonged symptoms are calling themselves, often describe ongoing exhaustion and shortness of breath.
In part, this can be explained by the way the virus can seriously affect the lungs.
The infection can cause fibrosis — scarred, stiff tissue that makes it difficult for the lungs to do their job of oxygenating the blood.
But changes to the heart can also contribute to these symptoms, says Linda Gallo, who is researching how coronavirus affects the heart, especially in people with diabetes.
Its impact on the heart still isn’t clear, Dr Gallo says, but studies published in recent weeks describe abnormalities in the hearts of patients who have completely cleared the virus.
“[The researchers] asked them about their just general wellbeing and a lot of the patients are commenting on just being generally exhausted and having shortness of breath, some of them having palpitations, atypical chest pain,” she says.
What’s more, many of these patients weren’t that sick with COVID-19 — most of them had managed their illness at home, rather than needing hospital treatment.
“Overall, the authors state that the cardiac effects were independent of severity and course of acute infection — which is concerning,” Dr Gallo says.
Dr Gallo is part of a study investigating the longer-term effects of COVID-19, especially on people with diabetes, and is currently looking for people who have had coronavirus to participate in a study.
Based on the information already available, she and her colleagues expect people with diabetes (either type 1 or type 2) are more likely have long-term effects.
What’s brain fog got to do with COVID-19?
Other persistent symptoms people report have to do with the brain: “brain fog”, sleeplessness and headaches.
While we don’t fully understand the neurological effects of coronavirus yet, we can learn a lot from the way the brain responds to other infections, says neuroscientist Lila Landowski of the University of Tasmania.
Fatigue, which is more than just a feeling of tiredness, and can be associated with things like a “foggy” brain, slowed reflexes and headaches, is usually a useful response to infections.
“There’s a good reason for that — mounting an immune response to fight an infection takes a huge amount of energy,” Dr Landowski says.
“The body wants you to do as little as possible, so you can conserve energy and divert it to the immune system.
“Then, once the infection is eliminated, the fatigue dissipates.
“However, in some people, the switch that returns the body back to normal seems to fail, resulting in chronic fatigue.”
Researchers are trying to understand more about this “switch” in the hope of developing effective treatments for those with chronic fatigue.
Whether or not coronavirus affects the brain more directly is another area of active research.
Vicki Lawson at the Doherty Institute is looking at whether the virus can get into the brain and, if so, which cells in the brain could it be infecting.
“Regardless of which cells it’s infecting, if it’s infecting cells in the brain, it could be causing damage, which could have long-term consequences,” Dr Lawson said.
Even if the virus doesn’t infect brain cells directly, inflammation caused by the virus could also cause damage to the brain.
Some experts are concerned the medium-term effects on the brain might have consequences that reach further.
In an article in the Journal of Alzheimers Disease Reports, experts raise the question of whether people who’ve had COVID-19, particularly those whose symptoms included loss of taste or smell, will be at greater risk of conditions including Alzheimer’s disease after they recover.
Another research group write in the journal The Neuroscientist: “We need to be prepared that COVID-19 could cause long-lasting debilitations [on neurological systems] after the infection has cleared.”