Herpes simplex virus type 1 (HSV-1) over-infection in patients with acute respiratory distress syndrome secondary to COVID-19 pneumonia: Impact on mortality.

Objective: Herpes simplex virus type 1 (HSV-1) reactivation have been described in patients with invasive mechanical ventilation and recently in patients with acute respiratory distress syndrome (ARDS) secondary to COVID-19 with higher rates of reactivation than were detected previously in critical care, and although the diagnosis of HSV-1 pneumonia is not easy, its presence is associate with an increase in morbidity and mortality. The objective of this study is to determinate if the identification of HSV-1 in lower airway of patients with ARDS secondary to COVID-19 have influence in clinical outcome and mortality.

Method: Two hundred twenty-four admitted patients in intensive care unit (ICU) of Complejo Hospitalario Universitario de Toledo diagnosed of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were reviewed and were selected those with mechanical ventilation who had undergone (BAL). It was registered all results of HSV-1 PCR (negative and positive).

Results: During the study period (November 28, 2020 to April 13, 2021) was admitted 224 patients in ICU diagnosed of SARS-CoV-2 pneumonia. Eighty-three patients of them had undergone BAL, with HSV-1 PCR positive result in 47 (56%), and negative result in 36 (43.4%). We performed pathological anatomy study in BAL samples on 26 of the total BAL realized. Typical cytopathic characteristics of HSV-1 were found in 13 samples (50%) and 11 of them (84.6%) have had HSV-1 PCR positive result. Thirty days mortality was significantly higher in the group of patients with HSV-1 PCR positive result (33.5% vs. 57.4%,  = 0.015). This difference was stronger in the group of patients with HSV-1 findings in the pathological anatomy study (30.8% vs. 69.2%,  = 0.047).

Conclusion: Our results suggest that ARDS secondary to SARS-CoV-2 pneumonia is highly associated to HSV-1 reactivation and that the finding of HSV-1 in lower airway is associated with a worst prognostic and with significantly mortality increase. It is necessary to carry out more extensive studies to determinate if treatment with acyclovir can improve the prognosis of these patients.