Anywhere from 31 to 69 percent [1] of COVID-19 patients end up with "long COVID [2]," aka the version of the illness with symptoms that linger for four weeks or longer, and the symptoms are serious [3]: extreme fatigue, loss of taste or smell, neurologic issues like brain fog, cardiovascular issues, and muscle and joint pain, to name a few. Organ damage [4] is also a possibility.
With so many people suffering from long COVID (sometimes called post-COVID syndrome), a new study [5] published in "Cell" offers some important information. The study has revealed four potential factors that increase your likelihood of developing long COVID based on information from over 200 patients. While more research is needed to confirm these factors (and potentially uncover others), the study is a big first step in understanding who gets long COVID and how to treat or possibly prevent it in future.
What Are the Risk Factors For Long COVID?
The study identified four factors that could increase your likelihood of developing long COVID:
- Type 2 diabetes, which is also a risk factor for severe COVID-19 [7]
- Level of coronavirus RNA in the blood early in the infection, which is an indication of viral load, or the amount of virus in the body
- Some types of autoantibodies. Autoantibodies are cells that mistakenly attack the body instead of antigens. Instead of protecting the body from an unfamiliar and potential harmful substance or cell, the autoantibodies weaken the body even further, as seen in conditions like lupus [8] and rheumatoid arthritis.
- Reactivation of the Epstein-Barr virus. The Epstein-Barr virus (EBV) is a type of herpes virus, and it's extremely common; according to the CDC [9], "most people get infected with EBV at some point in their lives" before it goes dormant. In some long COVID cases, researchers found that the virus was active once again.
Researchers uncovered these four factors by studying a primary group of 209 people who contracted COVID-19 in 2020 or early 2021 and were treated in the Seattle area. Based on survey results and health records, researchers found that 37 percent of this group had three or more symptoms of long COVID. Of that long COVID group, 95 percent had one or more of the above factors, lead investigator Jim Heath, PhD, told the "New York Times." He added that autoantibodies were associated with two-thirds of the long COVID cases, and the factors often overlapped.
The study is only a starting point. The researchers pointed out that they'd found associations between these four factors and long COVID, but further study is needed to understand the causal relationship — exactly how these factors leads to long COVID. In the "New York Times" analysis, experts not associated with the study also pointed out that the study's time frame (patients were followed for two to three months) may have been too short and that the majority of the patients had been hospitalized for COVID-19, raising questions about whether these factors are significant for people with initially mild cases of COVID-19.
The hope, though, is that this study opens the door for others and that these four initial factors provide the first hints of how to treat and potentially prevent long COVID.