Current WHO Phase of Pandemic Alert

Who Is WHO

The World Health Organization — WHO is the directing and coordinating authority for health within the United Nations system. It is responsible for providing leadership on global health matters, shaping the health research agenda, setting norms and standards, articulating evidence-based policy options, providing technical support to countries and monitoring and assessing health trends. In the 21st century, health is a shared responsibility, involving equitable access to essential care and collective defense against transnational threats.

Dr Margaret Chan, Director-General of WHO

Dr Margaret Chan


Dr Margaret Chan is the Director-General of WHO, appointed by the World Health Assembly on 9 November 2006.

Before being appointed Director-General, Dr Chan was WHO Assistant Director-General for Communicable Diseases as well as Representative of the Director-General for Pandemic Influenza.

Prior to joining WHO, she was Director of Health in Hong Kong. During her nine-year tenure as director, Dr Chan confronted the first human outbreak of H5N1 avian influenza in 1997. She successfully defeated the spate of severe acute respiratory syndrome (SARS) in Hong Kong in 2003. She also launched new services to prevent disease and promote better health.

Over the last year WHO has supported the Ministry of Health in developing disaster preparedness plans and evaluating its response to certain events.

What is an influenza pandemic?

A disease epidemic occurs when there are more cases of that disease than normal. A pandemic is a worldwide epidemic of a disease. An influenza pandemic may occur when a new influenza virus appears against which the human population has no immunity. With the increase in global transport, as well as urbanization and overcrowded conditions in some areas, epidemics due to a new influenza virus are likely to take hold around the world, and become a pandemic faster than before. WHO has defined the phases of a pandemic to provide a global framework to aid countries in pandemic preparedness and response planning. Pandemics can be either mild or severe in the illness and death they cause, and the severity of a pandemic can change over the course of that pandemic.

Detecting a new pandemic virus

Continuous global surveillance of influenza is key to the early detection of a virus with pandemic potential. WHO has a network of more than 120 National Influenza Centres in over 90 countries that monitor influenza activity and isolate influenza viruses in every region of the world. National Influenza Centres report the detection of an “unusual” influenza virus immediately to the WHO Global Influenza Programme and one of the five WHO Collaborating Centres. Rapid detection of unusual influenza outbreaks, isolation of viruses with pandemic potential and immediate alert to WHO by national authorities is critical to a timely and efficient response. Currently, WHO is producing and distributing regular  influenza A(H1N1) bulletins.

Current phase of alert in the WHO global influenza preparedness plan

In the 2009 revision of the phase descriptions, WHO has retained the use of a six-phased approach for easy incorporation of new recommendations and approaches into existing national preparedness and response plans. The grouping and description of pandemic phases have been revised to make them easier to understand, more precise, and based upon observable phenomena. Phases 1–3 correlate with preparedness, including capacity development and response planning activities, while Phases 4–6 clearly signal the need for response and mitigation efforts. Furthermore, periods after the first pandemic wave are elaborated to facilitate post pandemic recovery activities.

The current WHO phase of pandemic alert is 6.

Pandemic influenza phases

In nature, influenza viruses circulate continuously among animals, especially birds. Even though such viruses might theoretically develop into pandemic viruses, in Phase 1 no viruses circulating among animals have been reported to cause infections in humans.

In Phase 2 an animal influenza virus circulating among domesticated or wild animals is known to have caused infection in humans, and is therefore considered a potential pandemic threat.

In Phase 3, an animal or human-animal influenza reassortant virus has caused sporadic cases or small clusters of disease in people, but has not resulted in human-to-human transmission sufficient to sustain community-level outbreaks. Limited human-to-human transmission may occur under some circumstances, for example, when there is close contact between an infected person and an unprotected caregiver. However, limited transmission under such restricted circumstances does not indicate that the virus has gained the level of transmissibility among humans necessary to cause a pandemic.

Phase 4 is characterized by verified human-to-human transmission of an animal or human-animal influenza reassortant virus able to cause “community-level outbreaks.” The ability to cause sustained disease outbreaks in a community marks a significant upwards shift in the risk for a pandemic. Any country that suspects or has verified such an event should urgently consult with WHO so that the situation can be jointly assessed and a decision made by the affected country if implementation of a rapid pandemic containment operation is warranted. Phase 4 indicates a significant increase in risk of a pandemic but does not necessarily mean that a pandemic is a forgone conclusion.

Phase 5 is characterized by human-to-human spread of the virus into at least two countries in one WHO region. While most countries will not be affected at this stage, the declaration of Phase 5 is a strong signal that a pandemic is imminent and that the time to finalize the organization, communication, and implementation of the planned mitigation measures is short.

Phase 6, the pandemic phase, is characterized by community level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5. Designation of this phase will indicate that a global pandemic is under way.

During the post-peak period, pandemic disease levels in most countries with adequate surveillance will have dropped below peak observed levels. The post-peak period signifies that pandemic activity appears to be decreasing; however, it is uncertain if additional waves will occur and countries will need to be prepared for a second wave.

Previous pandemics have been characterized by waves of activity spread over months. Once the level of disease activity drops, a critical communications task will be to balance this information with the possibility of another wave. Pandemic waves can be separated by months and an immediate “at-ease” signal may be premature.

In the post-pandemic period, influenza disease activity will have returned to levels normally seen for seasonal influenza. It is expected that the pandemic virus will behave as a seasonal influenza A virus. At this stage, it is important to maintain surveillance and update pandemic preparedness and response plans accordingly. An intensive phase of recovery and evaluation may be required.

Go to WHO Pandemic preparedness for additional information

This description of the Organization,  the WHO Director-General and the current phase of alert in the WHO global  A(H1N1) Pandemic Influenza preparedness plan  information  comes directly from the World Health Organization’s web site.


Author: H. Sandra Chevalier-Batik

I started the Inconvenient Woman Blog in 2007, and am the product of a long line of inconvenient women. The matriarchal line is French-Canadian, Roman Catholic, with a very feisty Irish great-grandmother thrown in for sheer bloody mindedness. I am a research analyst and author who has made her living studying technical data, and developing articles, training materials, books and web content. Tracking through statistical data, and oblique cross-references to find the relevant connections that identifies a problem, or explains a path of action, is my passion. I love clearly delineating the magic questions of knowledge: Who, What, Why, When, Where and for How Much, Paid to Whom. My life lessons: listen carefully, question with boldness, and personally verify the answers. I look at America through the appreciative eyes of an immigrant, and an amateur historian; the popular and political culture is a ceaseless fascination. I have no impressive initials after my name. I’m merely an observer and a chronicler, an inconvenient woman who asks questions, and sometimes encourages others to look at things differently.