ORIGINAL ARTICLE: An Epidemiological Study of Confirmed H1N1 Admitted Cases in an Infectious Disease Hospital, Pune

Background: Pune was at the epicenter of Influenza A (H1N1) epidemic that struck the country during the middle of 2009. Initially all the persons with a positive PCR test for H1N1 were customarily admitted to the infectious disease hospital; but later on the facility for admission of severe category of patients was made available at two other hospitals in Pune city. Objectives: To know the epidemiological features of Influenza A (H1N1) during the initial stages of the epidemic. Method and Materials: All the patients admitted to the infectious disease hospital during June-October 2009 with a confirmed Influenza A (H1N1) PCR test were considered for the study. Statistical analysis: Mean, SD, Inter-quartile Range, Chi-square. Results: Less than 30 years comprised 87.6 percent and students were in majority (63.38%) out of the total 284 patients studied. The mean duration of illness for H1N1 was 6.8 days (inter-quartile range of 5-8 days). The clinical picture was almost similar in both male and female patients. Co-morbid conditions were observed in 15.8 percent patients. The complication rate in patients with respiratory co-morbid conditions was significantly higher. Initially, the proportion of patients with history of foreign travel was high; later on their proportion decreased to a very low level while an increase in the proportion of patients with history of contact with a known H1N1 patient was observed as the epidemic progressed. Nearly half of the families had not taken Oseltamivir chemoprophylaxis while 35.6 percent patients were administered Oseltamivir within 48 hrs of starting of symptoms. There was no mortality in the patients studied. Conclusions: A study of 284 confirmed cases of Influenza A (H1N1) in Pune city showed epidemiological features of the disease such as age, gender, history of contact, foreign travel, co-morbidity and complication rate and the Oseltamivir prophylaxis