---
title: Severe COVID Reactivates Dormant Herpes and Epstein-Barr Viruses
description: A Nature study of 1,154 hospitalized COVID patients found herpes and anellovirus reactivation in the first 40 days, and links anelloviruses to long COVID.
author: Dr Marina Nani (Editor-in-Chief)
updated: 2026-08-05T19:25:23.279Z
canonical: https://richhealthmagazine.com/article/severe-covid-reactivates-dormant-viruses-long-covid
image: https://cdn.nanimediahouse.com/covid-dormant-virus-reactivation-106888.webp
categories: Longevity & Science
content_type: News
region: Global
publication: Rich Health Magazine
schema_type: Article
---

Severe COVID-19 wakes up viruses that have been sitting quietly in the body for years, among them herpes simplex and Epstein-Barr, and one lesser known family of them keeps turning up months later in patients who go on to have long COVID. That is the finding of a [study of 1,154 hospitalized patients](https://www.nature.com/articles/s41586-026-10740-z) published in Nature on 5 August.

Most people carry between eight and twelve of these chronically infecting viruses at any time and never notice them. The patients here were treated at 20 US hospitals between May 2020 and March 2021, all of them unvaccinated when they enrolled, and were followed for a year after admission. Researchers led by Cole Maguire, working with the IMPACC study, sequenced RNA from blood cells, nasal swabs and, for patients on ventilators, samples taken from the airway, at up to ten visits across that year.

## Two Virus Families Woke Up in the First 40 Days

The reactivation was concentrated in the acute stage of illness, the first 40 days after hospital admission. One family is Herpesviridae, which includes herpes simplex 1, Epstein-Barr virus and cytomegalovirus. The other is Anelloviridae, a family most people have never heard of, which normally causes no disease at all.

Transcripts of herpes simplex 1, Epstein-Barr and cytomegalovirus were picked up commonly in that window, and far less often once patients reached convalescence, two months or more after admission.

## Reactivation Tracked With How Sick Patients Became

Patients were sorted into five groups by severity, from mild illness with a stay of a few days through to the 108 patients who died within 28 days. Viral reactivation tracked with that severity, and with immune changes and clinical outcomes. The paper is explicit that this is an association, not proof that the reactivated viruses made anyone sicker.

The pattern also runs against the standard assumption that reactivation of this kind happens mainly because illness or medication has suppressed the immune system. It was frequent in patients whose immune systems were working normally, alongside a broader rise in inflammation. Anellovirus activity was linked to a history of organ transplant, immunosuppressive medication, shock, intensive care admission and heart attack, but patients on immunosuppressive drugs made up only 17.4% of everyone who tested positive for it.

## Anelloviruses Turned Up Again in Patients With Long COVID

Reactivation did not stop when patients left hospital. It persisted into convalescence, and in that later period the researchers report an association between anellovirus activity and long COVID, describing anellovirus transcripts as a potential signature of persistent physical disability. Patients had been grouped by what they reported afterwards: minimal or no lasting effects, physical effects such as disability or fatigue, cognitive effects, or both together.

The same association was not there in the virus levels measured during the acute stage. The researchers note that comparison was limited, because patients carrying more chronic virus were more likely to die or drop out before reaching the convalescent stage where the long COVID signal appeared.

The researchers describe what they have produced as a set of immune, gene-activity and metabolic signatures of viral reactivation, the kind that could eventually help doctors judge who is likely to do badly with acute COVID-19 or long COVID, rather than an explanation of what drives either one.

## FAQ

**Q: What viruses can COVID-19 reactivate?**
In this study, severe COVID-19 was accompanied by reactivation of herpesviruses, including herpes simplex 1, Epstein-Barr virus and cytomegalovirus, and of anelloviruses, during the first 40 days after hospital admission.

**Q: What is an anellovirus?**
Anelloviruses are part of the group of eight to twelve chronically infecting viruses most people carry without symptoms. In this study their reactivation was linked to organ transplant history, immunosuppressive medication, shock, intensive care admission and heart attack, and, when detected later during recovery, to long COVID.