What if the long covid were explained … by a virus other than that of the covid? American scientists have established a link between the awakening of a virus dormant in the body, the Epstein-Barr virus (EBV), and the long forms of covid. This is what they explain in the review Pathogens.

A virus dormant in 95% of adults

But how does it work ? EBV is a virus of the herpes family, responsible in particular for infectious mononucleosis. It is present in 95% of healthy adults, in “dormant” form.

Indeed, after a first contamination which generally takes place in childhood or adolescence, the virus remains latent in the body. It does not cause symptoms, but can reactivate in cases of intense stress, immune deficiency but also inflammatory condition. Reactivation of the virus then causes fatigue, fever, headaches or neurological problems.

Read also: Latent viruses reactivated in astronauts in space

73% of long covid affected

And it is such a wake-up call that could occur in the presence of SARS-CoV-2, the virus responsible for covid. In the study published in Pathogens, the researchers recruited 185 people with covid, 56 of whom developed a long form.

They then examined their blood for the presence of specific antibodies to EBV, some of which are only detectable when the virus reactivates. Result: 73% of long covid patients had such antibodies indicating reactivation.

Read also: Covid: what sequelae to expect?

During or just after the covid

Next, the researchers wanted to estimate the date of the reactivation. They then discovered that this phenomenon seemed to occur soon after, or even at the same time as the covid infection.

Concretely, this means that “many long-term symptoms of covid may not be the direct result of SARS-CoV-2 virus but may be the result of EBV reactivation induced by inflammation of the covid “, write the scientists in their publication.

Screening for EBV to treat long covid

More robust and larger patient studies are still needed to understand the role of EBV in covid infections. But in the meantime, researchers are already calling to screen for reactivation of EBV in covid patients. Because treating it as quickly as possible could improve the management of long covid.