Nosocomial viral infections: myth or reality?@@@Virus nosocomiaux : mythe ou réalité ?

Prevention and treatment of ventilator-associated bacterial pneumonia resulted in numerous publications and guidelines. Respiratory viral "nosocomial" infections, consisting mainly in the reactivation of viruses from the herpes group, were described in the past two decades in the non-immunocompromised intensive care unit (ICU) patients. The actual pathogenesis of these infections has often been discussed with the assumption that they were the marker of severity of patients' illness rather than a real disease. To date, they are still underdiagnosed since rarely investigated in previously immunocompetent ICU patients. Several recent studies and meta-analyses suggested that they represent an independent risk factor for mortality and major morbidity to be considered as one separate disease entity by itself. Our purpose is to review respiratory viral infections occurring in the ICU focusing at the supposed pathophysiological mechanisms, risk factors, prognosis and ongoing studies regarding their management.