Researchers hunt for a long COVID diagnostic blood test
A big flush of funding from the National Institute for Health Research (NIHR) in the United Kingdom is pushing new research on ways to diagnose and treat long COVID. A University of Cambridge team receiving NIHR funding is now working on a blood test to objectively diagnose long COVID using immune biomarkers.
“Long COVID can have serious and debilitating long-term effects for thousands of people across the UK, which can make daily life extremely challenging,” says Sajid Javid, the UK government’s health and social care secretary. “This new research is absolutely essential to improve diagnosis and treatments and will be life-changing for those who are battling long-term symptoms of the virus.”
A team from the University of Cambridge is investigating whether there are any blood-based biomarkers that can be used to easily diagnose long COVID. Nyarie Sithole, co-lead on the research, says there is a real need to find a way to objectively track this emerging chronic condition.
“Because we currently have no reliable way of diagnosing long COVID, the uncertainty can cause added stress to people who are experiencing potential symptoms,” explains Sithole. “If we can say to them ‘yes, you have a biomarker and so you have long COVID’, we believe this will help allay some of their fears and anxieties.”
The Cambridge researchers have been following a number of long COVID patients for several months. Collecting regular blood samples, the researchers are currently looking at a particular immune biomarker that may be a specific sign of long COVID.
Cytokines are small proteins released by immune cells, and the initial stages of the research homed in on a particular cytokine produced by immune T cells in response to SARS-CoV-2 infection. The cytokine is detectable for several months following viral infection, and the researchers suspect it could be an effective way to test whether a person has been previously infected with SARS-CoV-2.
That pilot research also revealed another type of cytokine that seemed to be persistently present in long COVID patients and not patients who have completely recovered from COVID-19. It is this particular biomarker the researchers suspect could be a useful way to objectively diagnose those with long COVID.
The new NIHR funding will allow the Cambridge team to scale up their study and include up to 500 long COVID patients in their ongoing work. Sithole says the link between long COVID and a specific immune biomarker offers clues to the role the immune system may be playing in this new chronic condition.
“One of the theories of what’s driving long COVID is that it’s a hyperactive immune response – in other words, the immune system switches on at the initial infection and for some reason never switches off or never goes back to the baseline,” says Sithole. “As we’ll be following our patients for many months post-infection, we hope to better understand whether this is indeed the case.”
A trio of long COVID research projects at Oxford University also received NIHR funding boosts. These include an investigation into the effects of vaccination on long COVID and a detailed lung imaging study looking to understand the mechanisms behind persistent breathlessness in long COVID patients.