Background: Herpes simplex virus (HSV) is occasionally detected in the lower respiratory tract of patients in intensive care, but its clinical importance in such situations remains unclear. We did a prospective cohort study to define the prevalence, origin, risk factors, and clinical relevance of HSV in the respiratory tract of patients undergoing critical care.
Methods: We tested 764 patients admitted to intensive care for the presence of HSV in the respiratory tract, and assessed statistical relations between this virus and clinical variables.
Findings: HSV was detected by oropharyngeal swab in the upper respiratory tract of 169 (22%) of 764 patients, within 10 days of admission for 150 (89%) of these individuals. The virus was isolated in 58 (16%) of 361 patients whose lower respiratory tract was sampled. The presence of HSV in the throat was a risk factor for development of HSV infections in the lower respiratory tract (p<0.001). HSV was isolated most frequently in patients with severe disease. HSV in the throat was associated with acute respiratory distress syndrome (p<0.001) and with increased length of stay in intensive care (p<0.001).
Interpretation: Our data suggest that HSV reactivation or infection of the upper respiratory tract is frequent among patients in intensive care, and is a risk factor for development of lower respiratory tract infection with this virus, possibly by means of aspiration.