Presence of COVID-19 antibodies indicates past infection and predicts risk of future disease

The presence of viral antibodies to SARS-CoV-2 can be used as a marker to predict protection against excess risk of future disease, as well as mark past disease. This according to a new study by researchers from the Karolinska University Hospital, KUH, and KTH, among them SciLifeLab group leader Peter Nilsson (KTH). The study was supported by the SciLifeLab Autoimmunity and Serology Profiling unit.

To be able to plan ahead and put control measures in place in the fight against COVID-19, it is important to know the role of infection when it comes to predicting the risk of sick leave among infected individuals.

Early on in the pandemic, the degree of asymptomatic virus transmission was largely unknown and researchers from KUH and KTH, supported by the SciLifeLab Autoimmunity and Serology Profiling unit, designed a study to gather further data.

“One way to find out was to compare antibody levels with sick leave”, says Peter Nilsson.

In a massive study with 12 928 consenting employees at the Karolinska University Hospital, the researchers collected blood samples to determine the presence of antibodies and compared them to participant sick leave records. 

The researchers found that employees who had viral serum antibodies were not at any excess risk for future sick leave. At the same time, the presence of antibodies in participants was connected with a higher statistical chance of having been on sick leave in the weeks prior to testing. 

Although it might sound like an obvious conclusion, it is important to have actual data supporting the assumption that people with antibodies often have been on sick leave during the weeks prior to testing. 

The study was published in Nature scientific reports and can be read here.