The study included data from more than 50 researchers who followed 390 COVID-19 patients after their initial diagnosis. Unlike regular COVID symptoms, long covid symptoms can last for months, and researchers found they can include memory loss, gastrointestinal distress, fatigue, loss of smell, a lingering cough, and shortness of breath. Around 37% of patients in the study reported three or more of these symptoms months after infection, about 24% reported one or two symptoms, and 39% reported no symptoms.

The study offers four key indicators that correlate with a person being more at risk of getting long COVID and the lingering symptoms that affect them for months after recovery.

The four indicators are:

• Existing type 2 diabetes
  • If you have pre-existing type 2 diabetes you could be at risk of contracting long COVID, according to the study. Researchers warned it is likely only one of several other pre-existing medical conditions that could increase the risk of contracting long COVID.
    
• Circulating fragments of SARS-CoV-2 at the time of diagnosis
  •  A large amount of coronavirus RNA found in a person’s bloodstream early on during the disease could mean they are more at risk of getting long COVID. 
    
• Reactivation of the Epstein-Barr virus
  • The Epstein-Barr virus can cause mononucleosis, but usually stays dormant in the body. Having this virus, which the CDC calls “one of the most common human viruses” reactivated in your system at the time you are diagnosed with COVID-19, was correlated with an increase in risk of contracting long COVID, according to the study.
    
• The presence of specific autoantibodies directed against a person’s own tissue or organs.
  • Autoantibodies are created by a person’s immune system, but directed to attack their own tissue or organs. A larger presence of some autoantibodies in the body could indicate that a person has lower levels of protective antibodies against COVID, according to the New York Times.

Notably, the study found that women who developed long COVID tended to have more neurological symptoms, and that heart disease patients were more likely to lose their sense of smell and taste.

Although there is no cure for long COVID, the study suggested that giving people antiviral medication early in the course of the disease to deal with an excess of virus in a person’s system may help to decrease a person’s risk of experiencing long COVID symptoms.

The study’s authors warned that further research with more participants over a longer time frame is needed to confirm their findings.