Influenza Risk Assessment Tool


The Influenza Risk Assessment Tool is an instrument developed by the United States Centers for Disease Control and Prevention in 2010 with the purpose to systematically capture and evaluate data relating to influenza A viruses not at present circulating among people. IRAT was developed with assistance from global animal and human health influenza experts. Although it is not intended to predict the next pandemic influenza A virus, IRAT has contributed with input into prepandemic preparedness decisions.

Motivation

It was created in an effort to develop a standardized set of elements that could be applied for decision making when evaluating pre-pandemic viruses. The ultimate goal is the identification of an appropriate candidate vaccine virus and the preparation of a human vaccine before the virus adapts to infect and efficiently transmit in susceptible human populations. This pre-pandemic preparation would allow production of vaccine strategy that could prevent deaths and morbidity during a pandemic.

Approach

The IRAT uses a multiattribute, additive model to generate a summary risk score for each virus. For the development of IRAT, a series of ten risk elements and definitions were identified by a working group of international specialists in influenza virology, animal health, human health, and epidemiology. These elements were evaluated in three groups:
Virus:
Population:
Ecology:
Input is provided by U.S. government animal and human health influenza experts.

Implementation

IRAT was used to evaluate H7N9, H5N1, H9N2, and H3N2v to inform vaccine development and procurement decisions by the United States Government. The CDC has stated that IRAT is not meant to be predictive, and must be taken as an evaluative tool.

Legacy

The Tool for Influenza Pandemic Risk Assessment, a risk assessment tool developed by the World Health Organization, was modelled after IRAT.