Apr 12, 2005 (CIDRAP News) – The World Health Organization has published a new pandemic influenza preparedness plan that puts increased emphasis on the possibility of delaying a flu pandemic to buy time for improving the world´s defenses against it.

The 53-page plan is an update of one published in 1999. The revisions were prompted in part by the emergence of endemic H5N1 avian influenza with human cases in Asia and by the world´s experience with SARS (severe acute respiratory syndrome).

The plan´s introduction says the successful control of SARS in 2003 provided a "promising new paradigm" for managing epidemics, with rapid global and national actions coordinated by the WHO and facilitated by strong political support and good communication.

"The SARS experience suggests that coordinated global and national efforts could also be successful in addressing the emergence of a new human subtype of influenza—if not in containing a pandemic, then possibly in delaying its emergence to ´buy time´ for the implementation of preparations made in advance," the document states.

The WHO´s announcement of the plan says it addresses the possibility that a flu virus with pandemic potential, such as H5N1, will be around for a long time. "It also makes provision for the possibility of simultaneous occurrence of events with pandemic potential with different threat levels in different countries, as was the case in 2004 with poultry outbreaks of H7N3 in Canada and H5N1 in Asia."

The revised plan redefines the phases of a pandemic and gives more detailed descriptions of them. Where the previous plan had only two main stages, the interpandemic and pandemic periods, the new plan has three: interpandemic, pandemic alert, and pandemic.

The interpandemic period is divided into two phases and the pandemic alert period into three. In view of the H5N1 avian flu in Asia, the world now appears to be in phase 3, the first phase of the pandemic alert period. It is characterized by "human infection(s) with a new subtype [of flu virus], but no human-to-human spread, or at most rare instances of spread to a close contact."

For each phase, the plan lists objectives and actions for the WHO and for nations. The objectives and actions come under five headings: planning and coordination, situation monitoring and assessment, prevention and containment, health systems response, and communications. The WHO said this detailed guidance "should result in greater predictability of the measures to be taken by the various partners involved."

"Although it is not considered possible to halt the spread of a pandemic virus, it should be possible to minimize its consequences through advance preparation to meet the challenge," the report states.

The plan is based on a conference held in December 2004. Several other factors besides the SARS experience and the emergence of widespread avian flu influenced the plan, the document states. These include improved understanding of the evolutionary biology of flu viruses, new techniques for vaccine development and laboratory diagnosis, improved antiviral drugs, and ongoing revision of the International Health Regulations.

In addition, the perception of infectious diseases as threats to security has improved the chances of high-level political support for pandemic preparedness. Also, some countries have asked the WHO for more specific recommendations on preparedness, the report says.

WHO global influenza preparedness plan
The role of WHO and recommendations for national measures before and during pandemics

WHO/CDS/CSR/GIP/2005.5

The WHO global influenza preparedness plan has been prepared to assist WHO Member States and those responsible for public health, medical and emergency preparedness to respond to threats and occurrences of pandemic influenza.

It updates and significantly revises the Influenza pandemic plan. The role of WHO and guidelines for national and regional planning published by WHO in 1999. This new plan addresses the possibility of a prolonged existence of an influenza virus of pandemic potential, such as the H5N1 influenza virus subtype in poultry flocks in Asia, which persisted from 2003 onwards.

It also makes provision for the possibility of simultaneous occurrence of events with pandemic potential with different threat levels in different countries, as was the case in 2004 with poultry outbreaks of H7N3 in Canada and H5N1in Asia.The phases of increasing public health risk associated with the emergence of a new influenza virus subtype that may pose a pandemic threat have been redefined, actions for national authorities are recommended, and measures to be taken by WHO during each phase outlined.

This should result in greater predictability of the measures to be taken by the various partners involved, including WHO, during the different phases of the pandemic, and should improve international coordination and transparency in recommended national measures. Guidance is also provided to national authorities for developing their own pandemic plans in line with these phases.This document should be used in conjunction with the WHO checklist for influenza pandemic preparedness planning published by the World Health Organization in 2005.

Contents

- Executive summary

1. Introduction

2. Overview of new pandemic phases

3. Overarching goals, objectives and actions for each phase

Annex 1. Recommendations for nonpharmaceutical public health interventions
Annex 2. List of participants
Bibliography