INTRODUCTION: The swine flu or Influenza A H1N1 virus infection was first observed in Mexico and later spread quickly worldwide as a pandemic including India in 2009. It has emerged as a virulent pathogen leading to a considerable burden worldwide. The present study aims to analyze the clinic-epidemiological profile of the cases that tested positive in Tamil Nadu.
METHODS: During this retrospective study from 2022 to 2023, 6462 cases tested positive in Tamil Nadu, and the clinicalepidemiological profile was available for 6303 cases. The data was collected after approval from the Director of Public Health and Preventive Medicine of Tamil Nadu and the data was entered in Microsoft Excel and analysed using SPSS software version 21.
RESULTS: : In Tamil Nadu, the case positivity rate was 11.2% with a case fatality rate of 0.68%. The highest case positivity rate was in children <10 years(20%) followed by adults between 50-60 years of age(15.9%). Highest mortality rate was seen between 51-60 years (41.9%). The incidence was highest in Chennai followed by Coimbatore. The cumulative incidence was highest in September (46.5%) during monsoon. The highest mortality was observed in Category C patients (p-value <0.05) and in those who were initiated on treatment >2 days after the onset of symptoms (p-value <0.05).
CONCLUSION : Based on the findings of our study, we can hypothesize that the incidence of the Influenza A H1N1 case has a bimodal distribution with the highest fatality among the elderly. Stringent surveillance and preventive measures are needed during monsoon season and early initiation of treatment is necessary to reduce the mortality and morbidity.