Burden of herpes simplex virus encephalitis in the United States

Herpes simplex virus encephalitis (HSVE) is a disease of public health concern, but its burden on the healthcare of United States has not been adequately assessed recently. We aimed to define the incidence, complications and outcomes of HSVE in the recent decade by analyzing data from a nationally representative database. Healthcare Cost and Utilization Project databases were utilized to identify patients with primary discharge diagnosis of HSVE. Annual hospitalization rate was estimated and several preselected inpatient complications were identified. Regression analyses were used to identify mortality predictors. Key epidemiological factors were compared with those from other countries. Total 4871 patients of HSVE were included in our study. The annual hospitalization rate was 10.3 ± 2.2 cases/million in neonates, 2.4 ± 0.3 cases/million in children and 6.4 ± 0.4 cases/million in adults. Median age was 57 years and male:female incidence ratio was 1:1. Rates of some central nervous system complications were seizures (38.4%), status epilepticus (5.5%), acute respiratory failure (20.1%), ischemic stroke (5.6%) and intracranial hemorrhage (2.7%), all of which were significantly associated with mortality. In-hospital mortality in neonates, children and adults were 6.9, 1.2 and 7.7%, respectively. HSVE still remains a potentially lethal infectious disease with high morbidity and mortality. Most recent epidemiological data in this study may help understanding this public health disease, and the patient outcome data may have prognostic significance.