Nearly everyone carries dormant viruses picked up in childhood — herpesviruses, Epstein-Barr, cytomegalovirus and more — kept in check by a healthy immune system. A severe bout of COVID-19 can wake them all up, according to a study published today in Nature that tracked more than 1,000 people hospitalized with the disease.
Nearly half of the participants experienced reactivation of common latent viruses. Different viral families woke on their own timelines: Epstein-Barr virus and anelloviruses surged early, peaking shortly after hospital admission, while cytomegalovirus and herpes simplex viruses emerged around three weeks later, mainly in the respiratory system.
The 'most striking' result, says Resia Pretorius, a physiologist at Stellenbosch University in South Africa, is that reactivation happened even in people with otherwise healthy immune systems — overturning the assumption that it only occurs in immunocompromised patients. Even participants receiving immunosuppressive drugs were no more likely to experience viral awakenings, suggesting the stress of the coronavirus infection alone can overload the immune system.
Crucially, reactivation — of the typically harmless anelloviruses in particular — was linked to especially intense bouts of COVID-19 and to the development of long COVID. 'COVID is not really acting on its own,' says co-author Esther Melamed of the University of Texas at Austin. If further research shows the reactivated viruses can cause serious illness, the finding could open the door to new treatments for COVID-19 and long COVID.
