A pandemic is a global disease outbreak. It is determined by how the disease spreads, not how many deaths it causes.

When a new influenza A virus emerges, a flu pandemic can occur. Because the virus is new, the human population has little to no immunity against it. With no immunity in the population, the virus spreads quickly from person-to-person worldwide.

Characteristics and Challenges of a Flu Pandemic

Rapid Worldwide Spread

• When a pandemic flu virus emerges, expect it to spread around the world.
• You should prepare for a pandemic flu as if the entire world population is susceptible.
• Countries may try to delay the pandemic flu’s arrival through border closings and travel restrictions but they cannot stop it.

Overloaded Health Care Systems

• Most people have little to no immunity to a pandemic virus. Infection and illness rates soar. A substantial percentage of the world’s population will require some form of medical care.
• Nations are unlikely to have the staff, facilities, equipment, and hospital beds needed to cope with the number of people who get the pandemic flu.
• Death rates may be high. Four factors largely determine the death toll:
• The number of people who become infected
• The strength of the virus
• The underlying characteristics and vulnerability of affected populations
• The effectiveness of preventive measures
• Past pandemics spread globally in two or sometimes three waves.

Inadequate Medical Supplies

• The need for vaccines is likely to be larger than the supply. Those at highest risk will likely get the vaccine first.
• Early in a pandemic, the need for antiviral medications is likely to be larger than the supply. Those at highest risk will likely get antiviral medications first.
• A pandemic can create a shortage of hospital beds, ventilators, and other supplies. Alternative sites, such as schools, may serve as medical facilities to manage demand.

Disrupted Economy and Society

• Travel bans, event cancellations, and school and business closings could have a major impact on communities and citizens.
• Caring for sick family members and fear of exposure could result in significant employee absenteeism.

Information taken from the Flu.gov website.