Scientists have found a link between high levels of antiviral proteins and long Covid. This will help to improve efforts to diagnose the condition, which is debilitating for millions of people worldwide.
researchers reported on Wednesday that patients had persistently high levels of interferon-gamma, which is linked to fatigue, sore muscles, and depression.
Researchers have found that the protein can be used to detect Covid, and could also be investigated as a potential therapy for patients who complain of extreme fatigue.
Benjamin Krishna, a researcher at Cambridge University and co-author of this paper, said that the presence of interferon g could be used in certain patients to diagnose long Covid. It could also be used to treat the symptoms of patients.
Researchers have emphasized the need to identify “biomarkers” of long Covid – biochemical changes which are a sign of the disease. A study published in last month highlighted changes to the “complement system”, which is a grouping of proteins that helps the body fight infection.
Since the coronavirus epidemic began four years ago, Long Covid – defined as symptoms that persist for more than 12 week after the initial infection with Covid-19 – has been a growing burden on public health systems. The symptoms reported by sufferers include acute fatigue, shortness in breath, and cognitive impairment.
The study included patients from the 2020 cohort of a Covid clinic in Addenbrooke’s Hospital, Cambridge, England. The study tested 55 people who had symptoms, primarily fatigue, at least five month after contracting Covid-19.
Researchers found that Covid-19 infections triggered the production of IFN-g by white blood cell — and that this was persistent in the long Covid cohort. Over 60% of the sample group reported that they had reduced symptoms at least in part during the study. Their IFN-g level also decreased.
IFN-g is important in controlling the body’s reaction to pathogens. It is used to treat infections in patients whose immune system has been compromised by chronic disease granulomatous, a genetic disorder which makes them susceptible to dangerous fungal and bacterial infections.
Scientists say that the discovery of a biomarker for long Covid could offer hope to patients worried about their condition being dismissed by doctors.
Nyarie Sithole who established the Addenbrooke’s long Covid facility said, “When the clinic began, many people did not believe that long Covid existed.”
Although the causes of Long Covid are not yet known, it is estimated that 5 percent of those who contract this virus will be affected. The virus is linked to abnormalities of vital organs, microclots and reduced serotonin.
Aran Singanayagam is a respiratory doctor at Imperial College London. He said that the Addenbrooke research was “interesting” and proposed a new mechanism to treat long-term Covid. Singanayagam said that the evidence that IFN levels dropped as symptoms improved was one of the “strongest” aspects of the study.
Singanayagam said that further research would be needed to examine patients with symptoms other than fatigue, as it was unlikely that one mechanism like elevated IFN-g could “drive all forms of Covid” since he believed this was unlikely.
He noted that the study had not confirmed whether the protein is a “cause-driver” of Covid long — and therefore a good treatment target.