Pandemic Influenza Severity Assessment (PISA)
A WHO guide to assess the severity of influenza in seasonal epidemics & pandemics
This guidance has been developed by WHO to be used by Member States and WHO as part of the pandemic influenza risk management guidance (PIRM) to assess the severity of influenza in seasonal epidemics and pandemics, when sustained human-to-human transmission occurs.
This document is intended for use primarily by public health professionals at the national level, who perform or plan to perform national influenza severity assessments, and who can contribute to global influenza severity assessments. It is a living document that will be further updated as needed, and will serve as guidance for seasonal and pandemic influenza severity assessments.