New study suggests Covid-19 can awaken dormant viruses in some people
New Delhi: Many people recover completely after Covid-19, while others continue to struggle with fatigue, brain fog and other lingering symptoms for months. Scientists have been trying to understand why recovery varies so widely, and a new study has added another important clue. Published in Nature on August 6, researchers from the University of Texas at Austin found that severe Covid-19 may reactivate dormant viruses already present in the body, potentially contributing to Long Covid and other long-term health problems.
The findings suggest that SARS-CoV-2 can disrupt the immune system in ways that allow certain latent viruses to become active again. While the study does not establish a direct cause-and-effect relationship, it strengthens a growing theory about the biological changes that may follow severe Covid-19.
Study tracked 1,100 plus hospitalised patients
The observational study analysed data from 1,154 unvaccinated patients hospitalised with Covid-19 as part of the Immunophenotyping Assessment in a Covid-19 Cohort (IMPACC) study. Participants were treated across 20 hospitals in the United States between May 2020 and March 2021.
Researchers examined more than one billion biological data points, including nasal swabs, blood samples and respiratory specimens, to understand how the body responds to severe Covid-19 over time.
Reactivation of dormant viruses
Unlike many previous studies that relied on antibody testing, this research measured viral RNA, allowing scientists to identify viruses that were actively replicating inside the body.
The team detected RNA from 11 reactivated viruses within the first 40 days of hospital admission. Among the most notable were Epstein-Barr virus (EBV), cytomegalovirus (CMV), herpes simplex virus-1 and Anelloviridae.
These viruses often remain dormant for years after an initial infection and are normally kept under control by a healthy immune system.
How could this affect Long Covid?
Researchers found that reactivation of Anelloviridae, a virus family believed to remain dormant in around 90 per cent of people, showed a strong association with Long Covid and long-term physical disability.
The findings also support the theory that viral reactivation may contribute to persistent symptoms reported by some patients, including:
- Fatigue
- Brain fog
- Muscle aches
- Sleep disturbances
- General weakness
However, the researchers emphasised that viral reactivation is only one possible mechanism behind Long Covid, which is likely to have multiple underlying causes.
Severe illness showed greater risks
Among patients with severe Covid-19, those with CMV detected in the respiratory tract or EBV detected in the nasal cavity were more likely to die within one year than patients without evidence of these viral reactivations.
The researchers also observed links between viral reactivation and several serious complications, including kidney problems, stroke, bloodstream infections and shock.
Why do dormant viruses become active again?
Under normal circumstances, the immune system keeps latent viruses inactive throughout life. The researchers suggest that severe Covid-19 may disrupt this balance, allowing dormant viruses to begin replicating again.
Interestingly, the study found evidence that systemic inflammation, rather than immune suppression alone, may play a key role in triggering viral reactivation. This challenges a long-held belief that dormant viruses become active only when the immune system is severely weakened.
Findings may guide future treatment
Although the study does not prove that viral reactivation directly causes Long Covid, the researchers believe monitoring dormant viruses in hospitalised Covid-19 patients could help identify those at greater risk of long-term complications.
They also said the findings may eventually support the development of new treatment strategies that target both immune dysfunction and viral reactivation. However, further clinical studies are needed before such approaches become part of routine care.
The study offers one of the clearest insights so far into what may happen inside the body after severe Covid-19. While many questions remain unanswered, the findings provide researchers with another promising direction in understanding Long Covid and developing better ways to predict, prevent and manage its long-term effects.