Researchers have discovered a unique “signature” of Covid-19 present in the bloodstream of some individuals who contracted the virus. This marker was found to linger for months after the infection. Experts from Australia and Norway are delving into the reasons why certain individuals developed long Covid during the pandemic, while others fully recovered.

Long Covid is characterized by symptoms that persist for more than 12 weeks. Individuals affected may endure symptoms like fatigue, difficulty breathing, and cognitive issues for years. Currently, there is no available treatment for long Covid, and its precise mechanisms remain a mystery to medical experts.

Recent findings indicate that specific protein patterns linked to long Covid can be identified in the blood of patients months after their initial infection. Experts at News Medical refer to this as a “distinct immune signature in the blood.”

Published in the journal Communications Medicine, the study analyzed variations in inflammatory and neurological proteins among individuals, observing their responses to vaccination and reinfection.

The research focused on three groups in Victoria, Australia:

• People that didn’t have Covid
• People that had Covid and recovered fully
• People with long Covid

Blood samples were collected from participants six to nine months after their initial infection and before they received vaccinations. Both groups that had contracted Covid showed changes in immune-related proteins compared to those who had never been infected.

Following vaccination or subsequent infection, these affected proteins underwent further changes, indicating that their immune response might be modified long-term as a result of the infection. Those who had made a complete recovery showed less significant alterations than people experiencing long Covid.

The researchers observed: “We found that in both long COVID individuals and completely recovered people there were different changes in the level of some immune-related proteins after vaccination or re-infection compared with the response after the original infection suggesting a different immune response from the initial infection upon re-exposure.”

The long Covid cohort exhibited more enduring and pronounced changes, especially concerning their inflammatory and neurological proteins.

Receiving the vaccine appeared not to aggravate the responses of these proteins, furnishing researchers with evidence to endorse vaccinations for those living with long Covid.

Identifying this distinctive ‘signature’ of Covid present in the blood of long Covid sufferers brings researchers one step nearer to comprehending the condition and pinpointing biomarkers that could assist in diagnosing and treating long Covid.