HABP is a bacterial pneumonia that occurs 48 hours or more after admission; which was not incubating at the time of admission; and is not associated with mechanical ventilation 2,3 VABP is a pneumonia that arises more than 48 hours after endotracheal intubation 2,3 vHABP is a bacterial pneumonia that occurs 48 hours or more after admission; which was not incubating at the time of admission; where the patient subsequently experiences acute respiratory failure and requires ventilation