Long Covid is another public health crisis hidden in the pandemic, medical experts warned, with estimates of the patients suffering from the debilitating disease extending to more than 100m worldwide.
Scientists are in the early stages of looking for treatments that can relieve symptoms, target the still unclear causes, and get people healthy enough to return to work.
A meta-analysis of studies by Penn State researchers found that more than half of the 236 million people who had Covid-19 when the paper was published – which has since risen to 275 million – had symptoms that lasted longer than lasts six months.
Amitava Banerjee, a professor of clinical data science at University College London, said even after two years in the pandemic, we were “still caught in the spotlight”, focused on dashboards that monitor admissions and deaths in intensive care – but not the long Covid crisis not.
How long is Covid defined?
Long Covid is defined as suffering symptoms 12 weeks or more after diagnosis.
A recent UK study found that one in three of those admitted to hospital suffered from long covid disease a year later. Rachael Evans, a clinical scientist at the UK’s National Institute for Health Research, said the Covid-19 study to the hospital helped sort sufferers into subgroups and manage work to discover new medicines.
“It really underscores the urgent need for treatments to be investigated and for healthcare support to improve recovery,” she added. “None of us think Covid has had one mechanism and one treatment for a long time.”
What are the symptoms of long covid?
While patients suffer from a series of symptoms, the most commonly reported are fatigue and breathing problems. Some also experience damage to their organs and in the PHOSP study, one in 10 had clinically relevant cognitive impairment, often referred to as “brain fog”. Many symptoms resemble those of other post-viral diseases, including coronaviruses.
Margaret O’Hara, a trustee at patient group Long Covid Support, fell ill with Covid-19 in April 2020, after helping out on a critical care coronavirus ward. She experienced Covid for a year – and then, after contracting the disease in October 2021, she suffered again.
“Just fatigue doesn’t really begin to describe the intensity,” she said. “It’s so bizarre. Sometimes I get up in the morning and within an hour it’s like I’m numb. Like someone puts a chloroform hanky over my mouth and I have to lie down. ”
Women, people with obesity and those who have been on invasive mechanical ventilation are all more likely to develop long Covid.
It is not clear to what extent long-term vaccination helps prevent Covid – other than to reduce the likelihood of developing acute Covid-19 – but self-reported data from the UK’s Zoe Symptoms Detection App suggests that it halves the risk .
What causes long Covid?
A large part remain unknown. However, the PHOSP study provided an important clue that gave weight to a hypothesis that long Covid is caused by a sustained immune response. It found sufferers had elevated inflammatory markers. Researchers have found that the people with the worst long Covid, and those who experience brain fog, had the highest levels of inflammation.
Sir Stephen Holgate, University of Southampton professor and co-founder of Synairgen, a company that creates Covid-19 antiviral drugs, said MRI scans also showed inflamed organs.
“The body turns on itself as a result of all this inflammation during the Covid period and attacks its own tissue.”
There may be a genetic predisposition that determines who is most likely to suffer this type of immune response, so researchers are doing large genome-wide association studies that try to detect genes that patients have in common.
Another hypothesis is that the virus attacks the cells’ energy reserves, mitochondria. Subgroups can suffer for different reasons – or both hypotheses can be true at the same time.
Are there drugs that can be reused?
The UK’s NHS and major US health systems have established long Covid clinics, which often offers physiotherapy and mental health support, but has so far not had many pharmaceutical options.
Some doctors have tried to use drugs with few side effects that they believe may have an impact. It is as diverse as the symptoms, including antihistamines and cytokine blockers to address inflammation, antacids, beta blockers and anticoagulants. A recent small Cambridge study suggested that using a combination of “friendly bacteria” could help relieve long-term Covid’s bowel symptoms and improve overall well-being.
Banerjee intends to start a study in the new year, based on the recovery test that helped identify useful drugs for the treatment of acute Covid-19.
What is the future medicine in development?
Bill Hinshaw, CEO of Boston-based biotechnology Axcella Therapeutics, said there are few products in the pipeline for a long Covid – and even fewer that target muscle fatigue and weakness. Axcella and Oxford University are developing a drug to reduce inflammation and restore mitochondrial function. They hope to have clinical trial data by the middle of this year.
“You have a certain amount of energy in the battery,” Hinshaw said. “The virus comes in and takes over the battery and. . . damages it so that the battery can no longer hold the charge properly. ”
Others focus on a subset of patients. For example, digital therapeutic pioneer Akili Interactive is creating a game for people suffering from brain fog.
PureTech Health is working on a remedy for lung tissue damage, which is in a phase 2 trial. Michael Chen, head of innovation at London-listed biotechnology, said nearly half of those with a long covid had experienced shortness of breath, so “millions and millions” of lung lice may have signs.
“It’s a bit of a scary thought and a window to the public health crisis that could long be Covid in the future.”