Pan-canadian public health network council report and policy recommendations on the use of antivirals for prophylaxis during an influenza pandemic

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Annex 4: WHO / CPIP Pandemic Phase Definitions

WHO Pandemic Alert Phases:

6

Interpandemic Phase New virus in animals, no human cases	Low risk of human case	1
	Higher risk of human cases	2
Pandemic Alert New virus causes human cases	No or very limited human-to-human transmission	3
	Evidence of increased human-to-human transmission	4
	Evidence of significant human-to-human transmission	5
Pandemic	Efficient and sustained human-to-human transmission
SOURCE: Adapted from the WHO Global Influenza Preparedness Plan, 2005. (http://www.who.int/csr/disease/avian_influenza/phase/en/index.html)

Canadian Activity Levels

To facilitate consistency with the WHO phases and to tie in a descriptor of national levels of novel influenza subtype activity in Canada, the revised nomenclature for Canadian pandemic phases as identified in the CPIP is as follows.

The WHO Phase number reflects the international risk or activity level with respect to the new influenza virus subtype virus (i.e., Phases 1 to 6) and is determined by the WHO. The Canadian activity level indicator noted after the decimal point summarizes the observed new influenza virus subtype activity in Canada. These levels are classified as follows:

Localized and widespread activity have been combined in one “level” since the response activities associated with these two categories are not sufficiently different to warrant distinguishing between them.

For consistency with the WHO terminology, it was also agreed that the general categories of Interpandemic Period, Pandemic Alert Period, Pandemic Period and Post-Pandemic Period be adopted and used in public communications.

SOURCE: Canadian Pandemic Influenza Plan for the Health Sector, 2006. (http://www.phac-aspc.gc.ca/cpip-pclcpii/s02-eng.php)

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