Background: Influenza is truly an international disease. It occurs in all countries and affects millions of people every year. The Influenza A H1N1 in humans can be a mild illness or in some people it may result in serious, even life–threatening complications such as pneumonia, acute bronchitis, worsening of chronic conditions, respiratory failure and death. Objective:–

[1]To study profile of suspected cases of H1N1 in less a more than 60 years of patients admitted in the swine flu isolation ward of tertiary care  centre at S.M.S. Medical College & Attached Hospitals, jaipur, [2]To study the variation in clinical presentation if any

Methodology: This was a cross sectional observational study carried out in jaipur district of Rajasthan state, India. All suspected H1N1 virus infected 150 cases  admitted in the swine flu isolation ward of tertiary care  centre at S.M.S. Medical College & Attached Hospitals, jaipur during the period of 1st January to 31th December,2015 after taking verbal and written consent of the patients were enrolled in study. Before conducting the study approval was obtained from institutional ethical committee for human research.Data safety and confidentiality was also given due consideration. A predesigned semi–structured Performa was used. Detailed demographic and clinical data were recorded.Data was statistically analyzed using SPSS 24 software

Results:Out of total 150 cases, 88(58.67%) were >60 years of age groups as compared to 62 cases (41.33%) were <60 years of age. No significant difference was observed according to gender among the groups. Males were more 1.526 times in >60 years of age group as compared to females, 1.526 (0.794 to 2.933).Slightly higher in rural area as compared to urban as Odds ratio (95% Cl)1.260(0.650 to 2.443).  According to clinical features fever cough coryza, headache diarrhea were observed more in >60 years of age groups as compared to <60 years of age group. Shortness of breath was less in >60 years of age groups as compared to <60 years of age group (P=0.016S) TLC <4000, <1.4 PLT was less in >60 years of age groups as compared to <60 years of age group (14.29 % vs 85.71%) (P<0.001S). RT PCR (1=positive) was 17.33% in >60 years as compared to 82.67% in <60% years. (P<0.001S).The Wald criteria demonstrated that TLC<4000 and platelet count <1lakh

 The difference was statistically significant (P<0.05)

Conclusions:Influenza H1N1 infection was more common in older age group, more common in rural areas as compared to urban areas. During this epidemic almost 50% of H1N1 positive cases were in severe category and required ICU care and mechanical ventilation and they all had significant respiratory involvement in form of pneumonia, acute respiratory distress syndrome (ARDS) and respiratory failure with high mortality rate even at tertiary care hospital