COVID-19 May Reactivate Dormant Viruses

Nearly half of hospitalized patients had detectable reactivation of at least one chronic virus

September 7, 2026
3 min

The Pathologist

Overview

A longitudinal study found that nearly half of COVID-19 hospitalized patients had detectable reactivation of chronic viruses. The study does not confirm a causal link between viral reactivation and severe disease or long COVID.

Background

The reactivation of dormant viruses during acute COVID-19 illness raises important questions about the interplay between viral infections and disease severity.

Data Highlights

Finding	Percentage
Epstein-Barr virus reactivation (days 1-8)	24%
Human alphaherpesvirus 1 detection (days 19-23)	43% (endotracheal aspirates), 15% (nasal samples)
Cytomegalovirus in peripheral blood	8%
Chronic viral transcripts detected	550 of 1,148 patients

Key Findings

Nearly 50% of hospitalized COVID-19 patients had reactivation of at least one chronic virus.
Epstein-Barr virus reactivation was detected in 24% of patients during the first week.
Human alphaherpesvirus 1 was found in 43% of patients with endotracheal aspirates around days 19-23.
Cytomegalovirus was present in 8% of peripheral blood samples during the same period.
Herpesvirus and Anelloviridae transcripts were linked to greater COVID-19 severity.
Viral detection did not correlate with long COVID symptom groups.

Clinical Implications

Clinicians should remain aware of the potential for viral reactivation but should follow current guidelines that prioritize SARS-CoV-2-directed therapies.