Severe COVID-19 may reactivate dormant viruses, study finds

A large multi-omic study of 1,154 hospitalised COVID-19 patients found evidence that the infection can reactivate dormant viruses, including Herpesviridae, Enteroviridae and Anelloviridae, particularly in the first 40 days after hospitalisation. Times Now News reports that the reactivation was linked to COVID-19 severity.

Earlier research detected Epstein-Barr virus (EBV) reactivation in 27.1% of COVID-positive samples compared to 12.5% in COVID-negative. A 2025 study found EBV reactivation in 28.6% of Long COVID patients versus 11.3% of controls, suggesting a role in persistent symptoms. Another 2025 Cell Reports study linked higher EBV levels with long-term lung impairment.

However, not everyone with COVID experiences reactivation. A separate study of mild or asymptomatic cases found no detectable EBV in those with post-COVID symptoms. Researchers say the phenomenon occurs when the immune system is under stress, but it does not automatically mean dangerous disease. Scientists are still investigating the clinical significance.