A pandemic is a global disease outbreak. A flu pandemic occurs when a new influenza virus emerges for which people have little or no immunity, and for which there is no vaccine. The disease spreads easily person-to-person, causes serious illness, and can sweep across the country and around the world in a very short time. 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 they cannot stop it. An especially severe influenza pandemic could lead to 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 can range from school and business closings to the interruption of basic services such as public transportation and food delivery. A substantial percentage of the world's population will require some form of medical care. Healthcare facilities can be overwhelmed, creating a shortage of hospital staff, beds, ventilators and other supplies. Surge capacity at non-traditional sites such as schools may need to be created to cope with the demand. It is expected that such an event will quickly overwhelm the healthcare system locally, regionally, and nationally.4 An increased number of sick individuals will seek healthcare services. In addition, the number of healthcare workers available to respond to these increased demands will be reduced by illness rates similar to pandemic influenza attack rates affecting the rest of the population. Finally, healthcare workers and healthcare resources will also be expected to continue to meet non-pandemic associated healthcare needs. Collaboration with state and federal partners is vital to ensure that healthcare workers are adequately protected during an influenza pandemic. The goal of this document is to help healthcare workers and employers prepare for and respond to an influenza pandemic. The guidance document is organized into four major sections: Clinical background information on influenza; Infection control; Pandemic influenza preparedness; OSHA standards of special importance.