Burden of H1N1 influenza related mortality in a tertiary care centre

BACKGROUND: Influenza or the common flu is a commonly recognized cause of respiratory tract infection. A high level of clinical suspicion is required before a sample can be sent and often the diagnosis is established posthumously. In developing countries like India, data on disease burden of Influenza is severely lacking. It is a consequence of an under-estimation of Influenza as an important cause of illness and its natural course under-simplified to be a mild self-limiting illness. India was affected with a moderate severity compared to the other countries, although there was an insufficiency of epidemiological data from India during 2009 - 2010. Post-pandemic period, India was affected by major outbreaks in 2015 and 2017. We wanted to analyse the rate of positivity in a tertiary care centre amongst the total number of oropharyngeal swabs sent for Influenza virus testing. We also wanted to assess the mortality rate in Influenza positive cases in a tertiary care centre. METHODS: Data of oropharyngeal swabs sent for influenza virus testing through Real-Time Reverse Transcription Polymerase Chain Reaction from K.S. Hegde Medical Academy, Deralakatte was reviewed through a retrospective search of official influenza virus reports of Karnataka State along with the reports in Medical Records Department of K.S. Hegde Medical Academy in the time period of January 1^st 2016 to November 22^nd 2018. This study was done as a cross sectional retrospective study. RESULTS: Out of 127 oropharyngeal swabs that were sent during the study time period, 24 (18.9%) were positive for influenza virus. 18 (75%) cases were found to be H1N1 positive, 3 were H3N2 positive (seasonal strain) and remaining 3 were positive for Influenza B virus. 9 (37.5%) out of 24 cases of influenza succumbed to the disease, of which all were H1N1 positive (50% of the total H1N1 cases). CONCLUSIONS: H1N1 related mortality is a cause for concern for every healthcare providing institution. Influenza virus should be actively tested in patients with respiratory symptoms. During this COVID 19 related pandemic situation, there is a higher possibility of underdiagnosing H1N1. Lessons learnt from the past should be remembered and Influenza should not be neglected.