A five-year study of Influenza A (H1N1) pandemic 09 from Central India

Introduction : Influenza virus is a typical human pathogen causing serious respiratory infection. While declaring the last pandemic to be over in August 2010, World Health Organisation (WHO) conveyed that Pandemic Influenza A (HINI) virus would circulate as Seasonal Influenza virus for years to come. This study was undertaken to observe trends of Influenza A (H1N1) pandemic 09 over last five years in Vidarbha region of Maharashtra. Material and Methods: Throat/nasal/nasopharyngeal swabs/aspirates from clinically suspected cases of influenza like illness in category C received in the Viral Research and Diagnostic Lab (VRDL), Indira Gandhi Govt Medical College (IGGMC), Nagpur from October 2015 to September 2019 were included in the study. The samples were tested by reverse transcriptase real time polymerase chain reaction (RT-PCR). Clinical and epidemiological parameters were also noted. Results : Influenza A(H1N1)pandemic 09 positivity ranged from 03% to 21% in last five years. Males and females were almost equally affected except in 2019. Maximum positive cases were seen in age group of 41-60 years in 2015 (24%), 0-10 years in 2017(24%), 21-40 years in 2018 (9%) and 11-20 years (26%) in 2019 . Dual peaks of infection were seen in 2017, 2018 and 2019. Bhandara, Gondia and Akola districts had highest positivity . Discussion : Influenza A(H1N1)pandemic 09 is showing shift towards younger age groups and females slightly, both of which needs attention. Waning and waxing trend in last five years indicate unpredictable and changing epidemiology of the virus which should be studied further in details with respect to time, place, person and molecular characterisation of the virus. Keywords: Pandemic H1N1 trends Central India, Maharashtra