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Public Health Emergency Preparedness

This resource was part of AHRQ's Public Health Emergency Preparedness (PHEP) program, which was discontinued on June 30, 2011, in a realignment of Federal efforts.

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Table 8.1. How Seasonal Flu Differs from Pandemic Flu

Seasonal flu Pandemic flu
Outbreaks follow predictable seasonal patterns; occurs annually, usually in winter, in temperate climates. Occurs rarely (three times in 20th century—last in 1968).
Usually some immunity built up from previous exposure. No previous exposure; little or no preexisting 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 children and adults, along with other seasonal high risk groups, 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 circulating flu strains and available for annual flu season. Vaccine probably would not be available in the early stages of a pandemic.
Adequate supplies of antivirals usually available. Effective antivirals may be in limited supply.
Average U.S. deaths approximately 36,000/year. Number of deaths could be quite high (e.g., U.S. 1918 death toll approximately 675,000).
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) Severe pandemic 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.


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