Patients with long Covid (long Covid) have clear differences in immune and hormonal function from patients without the condition, according to a new study led by the Icahn School of Medicine at Mount Sinai and the Yale School of Medicine. Researchers have identified specific blood biomarkers that can accurately identify patients with long Covid.

Doctors from Mount Sinai first identified long Covid symptoms in 2020 when patients reported persistent problems after an initial, diagnosed Covid-19 illness.

These symptoms included cognitive impairment or “brain fog,” extreme fatigue, shortness of breath, and chronic pain. The US Centers for Disease Control and Prevention reports that one in 13 adults (or 7.5%) in the United States have long Covid symptoms that last more than three months after getting sick. Many of these patients have no clear cause for their symptoms, and this study, published in the journal Nature, provides new evidence for their causes.

The research

The researchers studied 271 patients between January 2021 and June 2022. They divided them into three groups, those with no previous SARS-CoV-2 infection, those who had fully recovered from a clinically confirmed case of Covid-19, and those with long-term active symptoms Covid for at least four months or more after confirmed infection. The mean time of long-term symptoms was twelve months from acute infection.

The researchers took blood samples from all patients, identified biomarker differences and similarities between the three groups, and then applied machine learning analyzes to better understand which biomarkers were most effective in allowing the algorithm to identify patients with long Covid. The algorithm was able to distinguish between people with and without long Covid with 96% accuracy and detect the condition based on distinctive features found in the blood of participants in the long Covid group. Some of the most striking differences of the long-Covid group from the other two groups were related to immune and hormonal dysfunction. This was characterized by biomarkers indicating abnormal T cell activity, reactivation of multiple latent viruses (including Epstein-Barr virus and other herpesviruses), and significant reductions in cortisol levels.

“These findings show that people with long Covid are living with a disease that is observable using the blood testing protocols defined in the study, but also varies from patient to patient depending on their specific medical history,” notes the lead researcher. and Professor of Rehabilitation and Human Performance at the Icahn Mount Sinai School of Medicine, David Putrino. He reminds us that this is a disease “that penetrates complex systems, such as the immune system and hormonal regulation. Complex diseases require complex therapeutic solutions and we need faster research to better understand long Covid and discover new and promising treatments.”