Clinical profile and outcome of recent outbreak of influenza A H1N1 (swine flu) at a tertiary care center in Hyderabad, Telangana

Background: Swine influenza, also called swine flu, hog flu, and pig flu, is an infection caused by any one of the several types of swine influenza viruses. The World Health organization (WHO) raised a worldwide pandemic alert for swine flu on June 11, 2009 that was a first of its kind in the past 70 years. In India, the index cases were reported from Pune, Maharashtra. We witnessed a recent outbreak in India during late 2014 and early 2015. Methodology: A retrospective study was carried out to describe the clinical profile and outcome of the confirmed cases of swine flu who were admitted at our center between December 10, 2014 and May 11, 2015. The cases were confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) on respiratory specimens. Results: A total of 514 patients with symptoms suggestive of swine flu were tested for hemagglutinin type 1 and neuraminidase type 1 (H1N1) out of whom 88 were positive, which accounted for 17.12% positivity. The mean age was 31.15 years with a range of 11-90 years, with equal distribution among males and females (males: 45, females: 43). The epidemic peaked in the month of January (n = 44.50%). Fever (95.45%) was the most common clinical manifestation followed by cough (85.22%), breathlessness (51.22%), and myalgia (50%). The majority were in category C (59.09%) based on the severity of the illness. All the patients were hospitalized and treated with oseltamivir. Of all the positive patients, 39 (44.31%) were advised home isolation after discharge for 5-7 days in view of the mild disease. Hypertension, diabetes, existing lung diseases, cardiovascular diseases, smoking habit, alcohol consumption, and pregnancy were found to be the major risk factors. Women in the third trimester of their pregnancy were found to be at a higher risk. Our study had an overall mortality of 14.77% (n = 13). Mortality was higher among pregnant women (n = 1/6, 16.66%) compared to nonpregnant women (n = 5/37, 13.51%). Multiple organ dysfunction syndrome (MODS) and acute respiratory distress syndrome (ARDS) were the most common causes of death. Conclusion: Swine flu activity has come down significantly, with a single case being reported in the month of April and none in May in 2015 at our center.