By Laura Mizoue

One of the scariest things about COVID-19 is its unpredictability. Younger, seemingly healthy, people can have severe complications and die. Even people who experience mild or no symptoms may be left with undetected organ damage that can cause future health problems.

A new study by researchers from SomaLogic, Massachusetts General Hospital, the Icahn School of Medicine at Mount Sinai and the Institute for Systems Biology shows how measuring proteins in the blood can predict COVID-19 severity and could be used to monitor recovery and long-term consequences on the heart. The study was funded in part by the Bill & Melinda Gates Foundation and Novartis, and a preprint is now available on medRxiv.

Before the pandemic, SomaLogic already created a groundbreaking laboratory developed blood test that can predict the four-year likelihood of heart attack, stroke, heart failure or death in someone with established heart disease or with known elevated risk from diabetes, kidney disease or older age. These are the same people who are at high risk of severe COVID-19. The validated test is based on the levels of 27 proteins in the blood.

In this study, the researchers analyzed blood collected from COVID-19 patients at the time of their initial presentation and found that the SomaLogic test predicted who was at highest subsequent risk of severe illness or death. The 27-protein test was better at predicting COVID-19 outcomes than standard prognostic markers of inflammation or heart damage, such as C-reactive protein or troponin.

The researchers also tested blood collected from individuals over the course of their illness and saw dramatic increases in cardiovascular risk during the first 4-8 days of infection that then decreased in survivors, although most individuals had not returned to normal risk levels by the end of the study. A period of “catastrophically high” risk (above 50 percent) typically lasted for 8-12 days.

Many people suffer from cardiac symptoms long after recovering from the virus and managing the health of these “long haulers” may be the next public health crisis. A growing number of studies have found heart inflammation or heart damage in COVID-19 survivors (even in young athletes who had asymptomatic disease), which can lead to arrhythmias, cardiac arrest or sudden death. A protein-based blood test could help assess when and if a person has truly recovered from COVID-19.

The finding that the same biologic processes which mediate heart risk outside of COVID-19 are also involved in COVID-19 itself leads to hope that some of the existing medicines for heart risk might help in COVID-19.