Clinical features of novel 2009 influenza A (H1N1) infection in Isfahan, Iran.

Background: During August 2009, novel H1N1 influenza virus began causing illness in Isfahan. Since rates of hospitalization and mortality due to the disease have varied widely in different countries, we described the clinical, radiologic, and demographic features of H1N1 hospitalized patients in a hospital in Isfahan.

Methods: This cross-sectional study was conducted in Alzahra Hospital during September 2009 to February 2010. Totally, 216 patients with confirmed, probable, or suspected cases of 2009 influenza A (H1N1) were admitted.

Results: Most patients were women (50.5%). Mean age of patients was 26.6 ± 19.5 years. The most common complains on admission were respiratory symptoms (91.6%, n= 198), fever (88.4%, n = 191), myalgia (65.7%, n = 142). In addition, 120 patients (56%) had at least one underlying medical disorder. Thirty-six patients (16.7%) died. Mortality was higher in children under 5 years old (10/36, 10%) and female cases (63.9% of died patients). Predicting variables affecting mortality were intensive care unit (ICU) admission and procalcitonin (PCT) > 0.5. Antiviral treatment was prescribed for 200 (92.5%) of the 216 patients.

Conclusions: Based on the findings of the present study, novel H1N1 influenza is highly prevalent among the youth. Moreover, it causes a relatively high morbidity rate. Therefore, people need to be encouraged to have vaccination against 2009 H1N1. Early diagnosis and treatment is related to less admission and shorter duration of hospitalization.