Reactivation of herpesviruses demonstrated in severely ill patients with acute COVID-19

EBV, CMV, and HHV-6 reactivation were found in a small cohort of severe COVID-19 patients.

Reactivation of herpesviruses is common in immunocompromised individuals. T cell immunity, in particular, is compromised in people with severe COVID-19 infection (Diao 2020).

Simonnet et al, at the University of Lille, France, studied the extent of herpesviruses reactivation in 34 people with severe COVID-19 being cared for in an ICU. Patients who were admitted to ICU for COVID-19 had repeated measurements of viral load for EBV, CMV, and HHV-6, via quantitative PCR on whole blood.

In 28 of the 34 patients (82%), EBV DNA was detected at least in one sample. The same was true in a smaller fraction of people for CMV (5/34, or 15%) and for HHV-6 (7/34, 22%).

Unfortunately, in some patients viral DNA was detected but could not be quantified. 

EBV reactivation occurred typically 4 days after ICU admission and was associated with a longer length of stay in the ICU. There was no association between ICU mortality and any viral reactivation. Viral reactivation also was not correlated with more severe clinical status (based on simplified acute physiology score). However, the relatively small size of this study gave the investigators little statistical power to recognize possible positive associations between viral reactivation and clinical severity, length of stay or likelihood of death. Another limitation of this study is that it did not include people with less severe acute COVID-19 infection.

This pilot study demonstrates that reactivation of several herpesviruses occurs in people severely ill with acute COVID-19 who require intensive care. Larger scale studies are needed to determine more precisely whether reactivation of EBV, CMV or HHV-6A/B increase the risk of certain adverse outcomes and, if so, whether antiviral treatments in people with reactivated infection might reduce the risk of these adverse outcomes.

Read the full article: Simonnet 2021