COVID-19 May Reactivate Dormant Viruses, Study Finds

The Cliff News | 17 August 2026

Severe COVID-19 infections may be triggering the reactivation of common viruses that have long lain dormant in the human body. A significant new study suggests this viral activity is associated with more severe illness and an increased risk of mortality among hospitalized patients. Furthermore, persistent viral activity could offer crucial insights into the debilitating fatigue and physical impairment characteristic of Long COVID.

Researchers meticulously analyzed blood samples and nasal swabs from 1,154 individuals hospitalized with COVID-19 between 2020 and early 2021. For a subgroup of patients requiring mechanical ventilation, lung secretions were also collected. These samples underwent screening to detect genetic material indicative of active replication by viruses other than SARS-CoV-2.

Dormant Viruses Reawakened by COVID-19

The findings revealed a striking prevalence of viral reactivation, with nearly half of the hospitalized participants showing evidence of at least one chronic virus reawakening. Among the viruses identified were common culprits such as cytomegalovirus, Epstein-Barr virus, herpes simplex virus type 1, and several types of anelloviruses.

Notably, this reactivation was not confined to individuals with compromised immune systems. The study indicates that such viral resurgence can also occur in people previously considered to have healthy immune defenses, highlighting the profound impact of severe COVID-19 on the body's viral landscape. Cytomegalovirus, Epstein-Barr virus, and anelloviruses are known to be extremely common, often acquired without noticeable symptoms and remaining dormant under immune system control for years.

Viral Reactivation Patterns and Long COVID Clues

Illness, stress, and a weakened immune system are known triggers for dormant viruses to resume replication. While earlier research had posited COVID-19's potential to initiate this process, previous studies lacked the scale to establish definitive patterns. This latest research, however, identified distinct timelines for viral reactivation during COVID-19 illness.

Epstein-Barr virus and anelloviruses were more frequently detected in the earlier stages of the illness. Conversely, cytomegalovirus and herpes simplex virus type 1 generally emerged later in the course of the disease, with peak detection occurring approximately three weeks after hospital admission. This differential timing may hold keys to understanding the varied presentations and lingering symptoms of Long COVID.