Clinico-epidemiological features of the hospitalized patients with 2009 pandemic influenza A (H1N1) virus infection in Saurashtra region, India (September, 2009 to February, 2010)

Background: The first case of 2009 pandemic influenza A (H1N1) virus infection in India was reported in May, 2009 and in Saurashtra region in August, 2009. We describe the clinico-epidemiological characteristics of patients who were hospitalized with 2009 influenza A (H1N1) infection in Saurashtra region. Materials and Methods: From September, 2009 to February, 2010, we observed 274 persons infected with 2009 influenza A (H1N1) virus who were admitted in different hospitals in Rajkot city. Real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) testing was used to confirm infection; the clinico-epidemiological features of the disease were closely monitored. Results: Of 274 patients, median age was 29.5 years, and 51.5% were males. Only 1.1% patients had recent travel history to infected region. Median time of five days was observed from onset of illness to influenza A (H1N1) diagnosis, while median time of six days reported for hospital stay. All admitted patients received oseltamivir drug, but only 16.1% received it within two days of onset of illness. One fourth of admitted patients were expired. The most common symptoms were cough (96.7%), fever (92%), sore throat and shortness of breathing, and coexisting conditions including diabetes mellitus (9.9%), hypertension (8.8%), chronic pulmonary diseases (5.5%) and pregnancy (5.5%) (P<0.05). Pneumonia was reported in 93% patients with chest radiography. Conclusion: We have demonstrated that infection-related illness affects both children and adults with survival of 74% patients. The median time from onset of illness to virus detection with use of real-time RT-PCR is five days. Pregnancy is found as a significant (P<0.05) risk factor for severe disease.