COVID-19 isn't going anywhere anytime soon. Most scientists now believe that SARS-CoV-2, the virus that causes COVID-19, will become endemic — meaning that it will continue to circulate in pockets of the global population for years to come, perhaps indefinitely, a bit like the seasonal flu. But even once the pandemic is over and new infections are relatively under control, this bizarre virus is likely to leave a lasting impact on the bodies it infects and the state of global health.
A small but significant number of people infected with COVID-19 go on to suffer from lingering symptoms, ranging from fatigue and headaches to other very unexpected symptoms. Known as long-COVID, the condition is still not fully understood but some scientists believe it has the very real potential to cause a tsunami of medical problems in the coming future.
Tim Spector is a Professor of Genetic Epidemiology at Kings College London who leads the ZOE COVID Symptom Tracker, an app designed for people to self-report their symptoms daily in a bid to better understand COVID-19. Since its launch in March 2020, the project has amassed a wealth of data on COVID-19 and helped to widely inform our understanding of the outbreak. It’s also gathered a bunch of insights into long-COVID.
According to his app, most people have got rid of their symptoms after an average of 10 or 11 days. However, between 5 to 10 percent of people go on to have symptoms from weeks and even months.
“There’s no doubt there are people who have had it one year on and have not recovered,” Professor Spector told IFLScience.
If you catch any viral infection, such as the flu, you can expect to feel tired and groggy for a few weeks after you fall sick. However, COVID-19 appears to affect many parts of the body in a myriad of ways, from brain fog and heart fluttering to tinnitus and hair loss.
“Nearly every symptom is being recorded,” he added.
“People are presenting with symptoms that doctors have never really seen before, such as really strange recurrent rashes in their toes, chilblains, it may look like they’re getting recurrent chickenpox, recurrent fevers that occur once a month that you only ever see in tropical disease,” Spector noted.
It’s not clear what’s causing this array of symptoms. Many cases are likely to be caused by generalized post-viral fatigue syndrome, but it’s also hypothesized that something else might be going on with COVID-19.
“It may be related to the virus itself and the body’s reaction to get rid of it,” explains Spector. “Particles of the virus, which may be dead, are stuck inside some of these people — in their skin, in their guts, in their brains — and the body is reacting to that, causing a mini auto-immune phenomenon.”
All of this might just be the tip of the iceberg, though. First of all, it’s not known what percentage of people may be suffering from these continued symptoms in, say, three or four years' time. Beyond this, the long-term implications of long-COVID remain gravely uncertain.
A number of scientists have published predictions that long-COVID could lead to a deluge of early-onset dementia cases in the coming decades. This might not just be a problem for those who fell severely sick with COVID-19, but even those who experienced a mild illness and lost their sense of smell. There is also the threat of long-term damage to the heart, lungs, and other major organs.
“Are people who had COVID-19 but got better after a few weeks — people who have lost their sense of smell, which we know is a sign of nerve damage — is that going to somehow trigger early dementia? We know there are links to people losing their smell and dementia,” said Spector. “We have no idea about that because we understand very little of how the virus causes this damage, but I think it’s an open question that my group at King's are working on and trying to raise money for.”
Spector and a host of other researchers from across the world are closely studying the phenomenon of long-COVID. One project will see the US National Institutes of Health invest $1.15 billion into the investigation of long-COVID. There’s also some good news. One survey published in May 2021 found that long-COVID symptoms may ease after receiving the vaccine. However, even if this remains true, long-COVID could become the source of a lurking global health concern for years to come.
“We certainly think we’ve moved into the endemic stage of the disease in the UK. We will be seeing regular waves of a few thousand cases. If 10 percent of those end up with persistent symptoms, that will be a regular medical problem that we need to start building for,” concluded Spector.