Clinical relevance of herpes simplex virus viremia in Intensive Care Unit patients.

OBJECTIVES: To determine the clinical relevance of herpes simplex virus (HSV) viremia episodes in critically ill adult patients.
METHODS: 1556 blood samples obtained for HSV PCR analysis in Intensive Care Unit (ICU) patients over 4 years were retrospectively analyzed, focusing on the comprehensive analysis of 88 HSV-viremic patients.
RESULTS: HSV DNA was detected in 11.8% of samples from the ICU. HSV viral loads remained below 5×10(2) copies/ml in 68.2% of patients and exceeded 10(4) copies/ml in 7.9%. Episodes of HSV-viremia correlated with immunosuppressed status and mechanical ventilation in 79.5% and 65.9% of patients, respectively. Only a subset of patients exhibited HSV-related organ damage, including pneumonia and hepatitis (10.2% and 2.3%, respectively). The mortality rate in HSV-viremic patients was not significantly increased compared to the overall mortality rate in the ICU (27.3% vs. 22.9%, p = 0.33). Only patients with high HSV viral loads tended to have a higher, though non-significant, death rate (57.1%, p = 0.14).
CONCLUSIONS: Our results suggest HSV viremia is common in ICU patients, potentially favored by immunocompromised status and mechanical ventilation. The global impact of HSV-viremia on mortality in the ICU was low. Quantifying HSV DNA may help identifying patients at-risk of severe HSV-induced symptoms.