HOW DOES SEASONAL FLU DIFFER FROM PANDEMIC FLU?

November 1, 2005

SEASONAL FLU	PANDEMIC FLU
Outbreaks follow predictable seasonal patterns; occurs annually, usually in winter, in temperate climates Usually some immunity built up from previous exposure	Occurs rarely (three times in 20^th century - last in 1968)   No previous exposure; little or no pre-existing immunity
Healthy adults usually not at risk for serious complications (the very young, the elderly and those with certain underlying health conditions at increased risk for serious complications)	Healthy people may be at increased risk for serious complications
Health systems can usually meet public and patient needs	Health systems may be overwhelmed
Vaccine developed based on known virus strains and available for annual flu season	Vaccine probably would not be available in the early stages of a pandemic
Adequate supplies of antivirals are usually available	Effective antivirals may be in limited supply
Average U.S. deaths approximately 36,000/yr	Number of deaths could be quite high (e.g., U.S. 1918 death toll approximately 500,000)
Symptoms:  fever, cough, runny nose, muscle pain.  Deaths often caused by complications, such as pneumonia.	Symptoms may be more severe and complications more frequent
Generally causes modest impact on society (e.g., some school closing, encouragement of people who are sick to stay home)	May cause major impact on society (e.g. widespread restrictions on travel, closings of schools and businesses, cancellation of large public gatherings)
Manageable impact on domestic and world economy	Potential for severe impact on domestic and world economy

For additional information visit: www.pandemicflu.gov