Market resolves to the official WHO-reported case fatality rate (CFR) in humans for the first 3 months of a declared H5N1 pandemic. If no pandemic occurs by 2026, market resolves N/A.
Case fatality rate estimates for prior influenza pandemics vary, but are typically less than 3%, even for the 1918 avian influenza pandemic. Attempts over the last 2 decades to model H5N1 mortality in a pandemic have given variable estimates, with some suggesting similar mortality rates to the 1918 influenza pandemic. Others predict higher rates, with one notable study from the Ontario health Department in 2008 suggesting that an HPAI H5N1 pandemic will have a higher mortality rate of 14-33%.
https://pubmed.ncbi.nlm.nih.gov/18477756/
The WHO’s mortality rate estimate is 60%.
https://www.who.int/news-room/questions-and-answers/item/influenza-h5n1
If the WHO releases figures before and after 3 months, I'll choose the data closest in time to 3 months after the pandemic is declared.