December 9, 2023

Framework for Influenza Pandemic Preparedness

Pandemic Influenza Preparedness Framework

The PIP framework is a set of tools that help guide different aspects of pandemic influenza preparedness. It includes intervals, risk assessment tools and other instruments for decision-making and action.

The intervals are based on events that occur along a hypothetical epidemic curve. Although the actual shape of the epidemic curve cannot be accurately predicted, up scaling designations allow the intervals to be generally applicable.

Phases of an Influenza Pandemic

In order to facilitate global communication of the risk to the public, WHO has developed a new pandemic phase framework for the period prior to and during an influenza pandemic. The framework divides the period into four global phases: interpandemic, alert, pandemic and transition.

During the interpandemic phase, there is no evidence of human infection with an influenza virus subtype with pandemic potential.

During this phase, a circulating animal influenza virus subtype poses only a moderate risk of infection in humans and/or limited spread of disease in close contacts.

During this phase, there is a global increase in disease activity associated with the emergence of a new strain of an influenza virus that has pandemic potential in humans, but the virus does not yet meet the criteria for moving to pandemic phase 3. There may be multiple outbreaks in different regions or communities with distinct epidemiological features.

Influenza Risk Assessment Tool (IRAT)

CDC’s IRAT is a simple additive, multiattribute assessment tool to prioritize pandemic influenza preparedness activities. Its 10 risk elements capture virus features, human attributes and response to viruses, and ecology and epidemiology of a zoonotic disease.

Katz emphasizes that IRAT is not intended to be a prediction tool for the next pandemic influenza virus. It can only evaluate viruses that are currently circulating in animals, and that are capable of affecting human health.

As an example, she explained that when SMEs evaluated A/duck/New York/1996, the virus received low average risk scores on both of the standard IRAT questions (risk to achieve sustained human-to-human transmission and risk to significantly impact public health if it does achieve sustained human-to-human transmission). The overall average IRAT score was 2.4. The IRAT process is designed to be flexible as scientific advances and technologies become available. CDC plans to update the IRAT framework periodically to accommodate new and emerging risk elements.

Pandemic Severity Assessment Framework (PSAF)

CDC developed the pandemic severity assessment framework to provide a common view of a pandemic using intervals that measure both clinical severity and transmissibility. It is intended to supplement the WHO influenza pandemic phases, which provide a general picture by aggregating epidemic curves from around the world. The framework provides commentary on several measures of clinical severity and transmissibility and guidelines for scaling them. It also includes a set of prepandemic planning scenarios based on the framework.

The initial assessment, done early in an outbreak when epidemiologic data are limited, uses a dichotomous scale of low- to moderate-level transmissibility and severity, similar to the Saffir-Simpson hurricane classification scheme. A later, more refined assessment occurs when reliable epidemiologic data are available and uses a 7-point scale of transmissibility and severity. The results of the assessments help determine whether community mitigation measures, such as school closures and quarantine of contacts, should be implemented. These measures can have a significant impact on the economy and social life.

Intervals for Pandemic Planning

In addition to the six pandemic intervals developed for government planning, the concept of intervals can be helpful in facility preparation. The intervals start with the initiation of a novel influenza virus and end with community recovery.

During the investigation interval, scientists look for evidence that a virus can cause human disease and assess its potential to cause a pandemic. Public health actions are focused on targeted monitoring and investigation of cases, co-investigations with animal health experts for zoonotic infections in animals and humans, and use of the IRAT to characterize the virus.

In this phase, it is important to develop and implement a plan to reduce the number of cases and their impacts. This includes assessing local business continuity and developing plans to minimize impact. Plans should be tested through exercises and reviewed on a regular basis. This will ensure that the plans are accurate and that changes can be made quickly. For example, changing the plan to reflect lessons learned from a real-world outbreak or an exercise can improve the effectiveness of the plan.

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Reassemble With Charles P. Jones

In the face of unprecedented challenges posed by the global pandemic, Charles P. Jones has emerged as a beacon of hope and a catalyst for positive change. His dedication to pandemic response and commitment to fostering a sense of community during these trying times have made him a pivotal figure in the fight against COVID-19. As the founder of, Charles has utilized his skills, experience, and passion to create a platform that connects individuals, fosters support networks, and provides valuable resources to those affected by the pandemic.


May 2024