Case series study of the clinical profile of H1N1 swine flu influenza.

OBJECTIVES To study the clinical profile of the H1N1 influenza cases attending government hospitals in South India and to study the impact of H1N1 infection on pregnancy outcome. MATERIALS AND METHODS A total number of 442 H1N1 positive patients (198 inpatients and 244 outpatients) from two government hospitals in Chennai, Madras Medical College & Government General Hospital and Institute of Child Health, Egmore were studied retrospectively during a period of 6 months from August 2009 to January 2010. RESULTS The rate of reported cases and hospitalization rates was highest among individuals aged 5 to 24 years. H1N1 cases were equally distributed in both the sexes in the adult population In our study 86.92% percent of patients with pandemic H1N1 influenza A met the case definition for influenza like illness (subjective fever plus cough and/or sorethroat). Similar to the western data bronchial asthma, pulmonary tuberculosis were found to risk factors for complications in H1N1 infection. The overall mortality rate was 1.8% and the most common cause of death in patients was due to pneumonia. Ventilator requirement was associated with poor prognosis in H1N1 patients. P value < 0.01. The percentage of persons > 65 years who were affected was far less ie 0.67% which is quite unusual in the case of seasonal flu. H1N1 pnuemonia was found to involve predominantly the lower lobe of lung. (p value < 0.01).The mortality rate among pregnant women with H1N1 infection was 25% and the fetal loss rate was 16.67%. There was an increased risk of H1N1 influenza infection during the third trimester of pregnancy. (p value-0.027). CONCLUSIONS Individuals with comorbid conditions, pregnancy were found to be severely affected. Hence individuals with risk factors need to be protected by vaccination.