Immunology: Prediction of long COVID in patients

An immune signature, which when combined with a history of asthma, age and some symptoms of COVID-19 could predict the risk of developing post-acute COVID-19 syndrome (PACS) — also known as long COVID — is reported in Nature Communications.

Acute SARS-CoV-2 infection can affect many organs and even after clearance of the infection, symptoms can persist long term. Around one third of individuals infected report symptoms that last for over four weeks following the initial infection. Manifestation of PACS in terms of observed symptoms can vary widely, with the most commonly reported symptoms being fatigue, shortness of breath and cognitive impairment. However, the reasons for developing PACS are currently not well understood.

Onur Boyman and colleagues followed a cohort of 215 individuals to investigate PACS; 175 tested positive for SARS-CoV-2 and 40 were healthy controls. Of the 175 individuals who tested positive, 134 were followed for up to one year after the initial infection. The authors identified 89 mild cases and 45 severe cases of COVID-19. 53.9% of mild and 82.2% of severe COVID-19 cases developed PACS, defined by the persistence of one or more COVID-19-related symptoms for more than four weeks after symptom onset. The authors analysed antibody levels and other clinical parameters, and identified a signature based on lower total immunoglobulin M (IgM) and immunoglobulin G3 (IgG3) levels, older age, history of asthma, and five symptoms (fever, fatigue, cough, shortness of breath, and gastrointestinal symptoms) reported during primary infection that could be used to predict the risk of developing PACS. They confirm this in an additional cohort of 395 individuals with COVID-19.

This study identifies markers that could predict the risk of developing PACS, but further research is needed to assess its utility in real world clinical settings, the authors conclude.