High incidence of Epstein–Barr virus, cytomegalovirus, and human-herpes virus-6 reactivations in critically ill patients with COVID-19

•Reactivations of EBV, CMV and HHV-6 are frequent in severe COVID-19.•EBV reactivation is associated with longer ICU length-of-stay.•EBV reactivation occurs early after ICU admission.•CMV reactivation occurs later after ICU admission and may require anti-CMV treatment. Systemic reactivation of herpesviruses may occur in intensive care unit (ICU) patients and is associated with morbidity and mortality. Data on severe Coronavirus disease-19 (COVID-19) and concomitant reactivation of herpesviruses are lacking. We selected patients admitted to ICU for confirmed COVID-19 who underwent systematic testing for Epstein–Barr virus (EBV), cytomegalovirus (CMV) and human-herpes virus-6 (HHV-6) DNAemia while in the ICU. We retrospectively analysed frequency, timing, duration and co-occurrence of viral DNAemia. Thirty-four patients were included. Viremia with EBV, CMV, and HHV-6 was detected in 28 (82%), 5 (15%), and 7 (22%) patients, respectively. EBV reactivation occurred early after ICU admission and was associated with longer ICU length-of-stay. While in the ICU, critically ill patients with COVID-19 are prone to develop reactivations due to various types of herpesviruses.