Pulmonary herpes simplex virus and cytomegalovirus in patients with acute respiratory distress syndrome related to COVID-19

Purpose Human herpesviruses, particularly cytomegalovirus (CMV) and herpes simplex virus (HSV), frequently reactivate in critically ill patients, including those with acute respiratory distress syndrome (ARDS) related to coronavirus disease 2019 (COVID-19). The clinical interpretation of pulmonary herpesvirus reactivation is challenging and there is ongoing debate about its association with mortality and benefit of antiviral medication. We aimed to quantify the incidence and pathogenicity of pulmonary CMV and HSV reactivations in critically ill COVID-19 patients. Methods Mechanically ventilated COVID-19 patients seropositive for CMV or HSV were included in this observational cohort study. Diagnostic bronchoscopy with bronchoalveolar lavage was performed routinely and analyzed for alveolar viral loads and inflammatory biomarkers. Utilizing joint modeling, we explored the dynamic association between viral load trajectories over time and mortality. We explored alveolar inflammatory biomarker dynamics between reactivated and non-reactivated patients. Results Pulmonary reactivation (> 10 4 copies/ml) of CMV occurred in 6% of CMV-seropositive patients (9/156), and pulmonary reactivation of HSV in 37% of HSV-seropositive patients (63/172). HSV viral load dynamics prior to or without antiviral treatment were associated with increased 90-day mortality (hazard ratio [HR] 1.24, 95% confidence interval [CI] 1.04–1.47). The alveolar concentration of several inflammatory biomarkers increased with HSV reactivation, including interleukin (IL)-6, IL-1β, granulocyte colony stimulating factor (G-CSF), and tumor necrosis factor (TNF). Conclusion In mechanically ventilated COVID-19 patients, HSV reactivations are common, while CMV reactivations were rare. HSV viral load dynamics prior to or without antiviral treatment are associated with mortality. Alveolar inflammation is elevated after HSV reactivation.