People struggling to recover from long Covid are not just trying to fight off the remnants of the SARS-CoV-2 virus. Their immune system may also struggle to beat other viruses.
Since COVID-19 survivors first began reporting the long-term effects of the disease, many of their remaining symptoms, such as fatigue and brain fog, have been compared to chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME).
Recent research shows, it is not a coincidence. In some cases, the two chronic diseases may have a common root. A study conducted on 185 COVID-19 patients in the United States has found that most of the patients with long COVID-19 tested by the researchers tested positive for reactivation of the Epstein-Barr virus (EBV).
EBV is one of the most common viral infections. Most people around the world contract the virus at some point in their lives, and after the acute phase of infection, the inactivated version of the virus stays in the body for life. Quoted from Science Alert, sometimes EBV can reactivate and cause flu-like symptoms, such as during periods of psychological or physiological stress such as during the current pandemic.
"We ran serological tests for the Epstein-Barr virus on COVID-19 patients at least 90 days after testing positive for SARS-CoV-2, and then compared the EBV reactivation rates of those with long Covid symptoms with those without," said biologist Jeffrey Gold. from the World Organization.
"We found that more than 73% of COVID-19 patients who experienced long Covid were also positive for EBV reactivation," he said.
Moreover, many of the reported symptoms are very similar to those arising from EBV reactivation, including extreme fatigue, frequent skin rashes and Raynaud's phenomenon leading to decreased blood flow to the fingers and toes.
Although the sample size studied here is very small, the results suggest many of the symptoms of long Covid may not actually arise from SARS-CoV-2 itself, but from reactivation of EBV, potentially triggered by the widespread inflammation of COVID-19.
Among 185 randomly selected COVID-19 patients, the researchers found nearly a third experienced symptoms lasting for months, sometimes even more than a year. In a random sample of study subjects, nearly 67% of long Covid patients showed antibodies to EBV reactivation in their blood. At the same time, only 10% of patients without long Covid tested positive for EBV reactivation.
The researchers also tested a second group of people diagnosed with COVID-19 21-90 days earlier. Even in these short-term subjects, the EBV reactivation ratio appeared to be similar.
"We found similar rates of EBV reactivation in those who had long Covid symptoms for months, starting just weeks after testing positive for COVID-19," said molecular microbiologist David Hurley of the University of Georgia.
"This suggests that reactivation of EBV may have occurred simultaneously or immediately after COVID-19 infection."
Earlier this year in Wuhan, China, researchers also found evidence that EBV reactivation may be associated with COVID-19 in its early stages. Within two weeks of COVID-19 infection, more than 50% of the 67 COVID-19 patients in the study showed signs of EBV reactivation. This coinfection of EBV and SARS-CoV-2 is associated with more severe symptoms. In addition, another small ICU study in Europe showed that positive EBV DNA was found in approximately 87% of the 104 COVID-19 patients examined.
The researchers behind the study think that testing for EBV antibodies in new COVID patients may be feasible. If these patients show signs of EBV reactivation, they may be able to receive further medical care to protect them from the risk of experiencing a severe or prolonged long course of Covid.
Of course, not all people with long Covid will show reactivation of EBV. Some recovered COVID-19 patients can show evidence of EBV reactivation without suffering any symptoms. Therefore, tests like these can help identify where the health risks are greatest and help doctors treat them appropriately.