Long Covid is defined as Covid symptoms continuing beyond 12 weeks, with some sufferers battling the condition for multiple years, experiencing symptoms such as fatigue, breathlessness, and brain fog. There is currently no treatment available for long Covid, and its mechanisms remain unclear to healthcare professionals, prompting scientists in Australia and Norway to investigate why some people develop it while others recover completely. The study involved three groups: people who didn't have Covid, people who had Covid and recovered fully, and people with long Covid, with blood samples taken between six and nine months following initial infection and prior to vaccination.
Scientists examined inflammatory and neurological protein variations and tracked how these responded to vaccination and reinfection, finding protein patterns associated with long Covid could be detected in the blood of those infected several months post-initial infection. Both cohorts who had contracted Covid displayed alterations in their immune-related proteins compared to people who had never fallen ill, and 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. According to Daily Express - Health, researchers described different changes in immune-related proteins after vaccination or reinfection in long Covid and recovered individuals, suggesting a different immune response upon re-exposure.
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.
People who made a complete recovery showed less significant alterations than people experiencing long Covid, with the long Covid cohort exhibiting more enduring and pronounced changes, especially concerning inflammatory and neurological proteins. The specific proteins or biomarkers constituting the distinctive immune signature remain unidentified, and it is unclear how this signature correlates with symptom severity or duration, or what potential clinical applications, such as diagnostic tests, might emerge from this discovery.