Epidemiological trends of influenza A H1N1 (2022–2024): a retrospective study

Influenza A H1N1 is a contagious viral infection caused by Influenza A virus subtypes (most commonly H1N1). This study analyses patient data from the Influenza A H1N1 cases reported in Punjab, India, for the years 2022, 2023, and 2024, focusing on distribution patterns, demographic characteristics, and mortality trends. This retrospective, record-based study included data on the epidemiological characteristics of Influenza A H1N1 cases in the years 2022, 2023, and 2024 which were descriptively analysed using data from the Integrated Disease Surveillance Programme (Directorate of Health and Family Welfare, Punjab). The analysis revealed a higher incidence among adults aged 51–70 years and district Ludhiana reported the highest number of cases. It also marks the seasonal shift in the pattern of virus outbreaks. This study reveals a marked seasonal shift in the incidence of Influenza A H1N1 in Punjab, with a higher prevalence among individuals aged 51–70 years. The findings underline the importance of targeted vaccination campaigns before peak months for high-risk groups and year-round surveillance as well as close caution should be exercised in H1N1 patients with co‑morbidities.