Pandemic risk characterisation of zoonotic influenza A viruses using the Tool for Influenza Pandemic Risk Assessment (TIPRA).

A systematic risk assessment approach is essential for evaluating the relative risk of influenza A viruses (IAVs) with pandemic potential. To achieve this, the Tool for Influenza Pandemic Risk Assessment (TIPRA) was developed under the Global Influenza Programme of WHO. Since its release in 2016 and update in 2020, TIPRA has been used to assess the pandemic risk of 11 zoonotic IAVs across ten evaluation rounds. Notably, A(H7N9), A(H9N2), and A(H5) clade 2.3.4.4 viruses were re-evaluated owing to changes in epidemiological characteristics or virus properties. A(H7N9) viruses had the highest relative risk at the time of assessment, highlighting the importance of continuous monitoring and reassessment as changes in epidemiological trends within animal and human populations can alter risk profiles. The knowledge gaps identified throughout the ten risk assessments should help to guide the efficient use of resources for future research, including surveillance. The TIPRA tool reflects the One Health approach and has proven crucial for closely monitoring virus dynamics in both human and non-human populations to enhance preparedness for potential IAV pandemics.