Per information provided today by the WHO:
The Emergency Committee, established in compliance with the International Health Regulations (2005), held its second meeting on 27 April 2009. The Committee considered available data on confirmed outbreaks of A/H1N1 swine influenza in the United States of America, Mexico, and Canada. The Committee also considered reports of possible spread to additional countries. On the advice of the Committee, the WHO Director-General has raised the level of influenza pandemic alert from the current phase 3 to phase 4.
OSHA provides this information on their website regarding pandemic flu outbreaks
A pandemic is a global disease outbreak. An influenza pandemic occurs when a new influenza virus emerges for which there is little or no immunity in the human population; begins to cause serious illness; and then spreads easily person-to-person worldwide. A worldwide influenza pandemic could have a major effect on the global economy, including travel, trade, tourism, food, consumption and eventually, investment and financial markets. Planning for pandemic influenza by business and industry is essential to minimize a pandemic’s impact.
It is difficult to predict when the next influenza pandemic will occur or how severe it will be. Wherever and whenever a pandemic starts, everyone around the world is at risk. Countries might, through measures such as border closures and travel restrictions, delay arrival of the virus, but cannot stop it.
During a pandemic, transmission can be anticipated in the workplace, not only from patient to workers in health care settings, but also among co-workers in general work settings. A pandemic would cause high levels of illness, death, social disruption, and economic loss. Everyday life would be disrupted because so many people in so many places become seriously ill at the same time. Impacts could range from school and business closings to the interruption of basic services such as public transportation and food delivery.
Education and outreach are critical to preparing for a pandemic. Understanding what a pandemic is, what needs to be done at all levels to prepare for pandemic influenza, and what could happen during a pandemic helps us make informed decisions both as individuals and as a nation. Should a pandemic occur the public must be able to depend on its government to provide scientifically sound public health information quickly, openly and dependably. For additional information on pandemic influenza, see One-stop access to U.S.government avian and pandemic flu information.
A Pandemic Flu FAQ can be found HERE