Research carried out at Imperial College London, UK, suggests that long Covid could soon be diagnosed by a simple blood test.
Pilot data has identified autoantibodies in the blood of long Covid patients. These autoantibodies were not found in the blood of people who recovered quickly from the virus or had never tested positive for the disease.
Unlike regular antibodies that help to fight off infections, autoantibodies mistakenly target and react with a person’s own tissues and organs. They have been linked to a number of autoimmune conditions, such as Grave’s disease, arthritis and some cases of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).
There is currently no objective diagnostic test for people with long Covid, which can make it difficult for patients to find a diagnosis. The Imperial researchers hope that their work could be the first step towards a point-of-care diagnostic blood test for long Covid.
Imperial College London professor of immunology Danny Altmann, who is leading the research, said: “I’m famously optimistic, so I’d hope that within six months we’d have a simple blood test that you could get from your GP, and that I think could have quite a big impact for people who don’t feel they’ve managed to convince their GP or accessed specialist care because instead of being my word against yours, it has a diagnostic test.”
Altmann has also expressed concern at what the UK’s relaxing of Covid-19 restrictions could mean for cases of long covid.
He said: “One of the things we know for absolute certain is that long Covid can ensue from any form of infection – asymptomatic, mild, severe, so if we’re heading into a phase of 100,000 cases per day, in the coming months and we’re saying that 10%-20% of all infections can result in long Covid, I can see no certainty that we’re not brewing those long Covid cases despite having a vaccinated population.”
It’s not yet clear how prevalent long Covid is among fully or partially vaccinated individuals.
Long Covid clinics
In May, the UK Department of Health vowed to establish 89 long Covid clinics in England to help patients with specialist care, setting guidelines that the clinics should accept both hospitalised and non-hospitalised patients.
Despite this, research from BBC Panorama has found four of the clinics only see patients who were originally hospitalised with the disease.
Ten of the clinics also had patients who had been waiting over 100 days to be seen, with the longest facing a wait of 191 days.
The Department of Health said: “The government rapidly provided specialist care for acutely ill Covid-19 patients at the start of the pandemic and we’ve matched that speed and scale in our support for people with long Covid.”
It said it had backed scientists with over £50m in research funding to better understand the long-term effects of Covid-19.
NHS England said it has invested more than £134m in long Covid services and is setting up 15 paediatric hubs.
Meanwhile, Scotland and Wales do not yet have any specialised long Covid clinics. The Scottish Government says it is investing in research rather than long Covid services. Northern Ireland’s first long Covid clinics will open in October this year.
Long Covid research could benefit chronic fatigue patients
ME/CFS appears to be triggered by an acute episode of viral illness in the vast majority of patients, leading many commentators to draw a link between ME/CFS and long Covid.
ME Association medical adviser Dr Charles Shepherd says: “Many long Covid patients are coming to us because they’re finding it very difficult to access advice on the ME/CFS type symptoms they’re experiencing, like brain fog and post-exertional malaise.
“Some of these people are now finding their diagnosis is being changed from long Covid into ME/CFS.”
The ME Association Ramsay Research Fund currently covers all the basic running costs of the ME Biobank at the Royal Free Hospital, a bioresource of anonymised blood samples from volunteers diagnosed with ME/CFS. The biobank aims to enhance research into ME in relation to pathophysiology, biomarkers and therapeutic approaches, and may one day find a place in long Covid research as well.
There isn’t sufficient evidence yet to say that any autoantibody or cluster of autoantibodies can be used as a definitive diagnostic marker of ME/CFS, so there currently isn’t any objective diagnostic blood test available in the way that there could soon be for long Covid. Some people with ME/CFS have been found to have low levels of antinuclear antibodies, which attack healthy proteins within the nucleus.
Shepherd says: “I would have thought in something like [Altmann’s research] it would be useful to have another control group of people with an overlapping condition like ME/CFS. Then you could test some samples in our biobank to see whether or not they’re producing the same results.”