Clinical Profile of Patients Admitted with Swine-Origin Influenza A (H1N1) Virus Infection: An Experience from A Tertiary Care Hospital

Background: Pandemic influenza A (H1N1) 2009 has posed a serious public health challenge world-wide. H1N1 critical illness mostly affects young patients and is often fatal. Objective: Primary objective was to study clinical profile of the patients admitted with confirmed H1N1 swine flu infection. Secondary objective was to observe the risk factors associated with complications like need of mechanical ventilation and or death among H1N1 infected patients. Material and Methods: A prospective observational study was conducted in a tertiary care teaching hospital from June 2009, to December, 2011. H1N1 infection was confirmed by reverse transcriptase PCR. Statistical analysis was done by SPSS, version 11. Binary logistic regression was used to find out independent risk factors for morbidity. Results: Total 495 patients were tested for H1N1 infection. Among them, 115 (23%) were positive and 88(76%) required admission. Median age of cohort was 29 years and 87% of the patients were below 54 years of age. Most common presenting symptoms were fever (98%), followed by cough (86%) and sore throat (54%). Out of 88 patients, 14 (16%) required mechanical ventilation and 6(6.8%) died. Lymphopaenia (Lymphocytes