| Pandemic Influenza |
Typical Seasonal Flu |
| Comes from a novel virus to which no one, or few people, have any immunity |
Circulating viruses slightly mutate year to year |
| Attack rate may be as high as 30% of population |
Attack rate 5-20% of population
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| Patients are sicker for a longer period time |
Illness usually lasts 1 to 2 weeks |
| Limited vaccine availability |
Vaccine available prior to illness in population |
| May be resistant to some antivirals |
Several antiviral medications are available |
| Excess mortality (3 to 7 times normal rate) |
Normal flu mortality—36,000/year in U.S. |
| Patients may present with primary viral pneumonia |
Pneumonia is usually a later complication |
| May be severe in all ages |
Severe in the very old and the very young |
| Can occur at any time of the year |
Seasonal—occurs in the winter |
| May have more than one wave of illness |
Usually just one wave of illness |
| Spreads rapidly throughout the world |
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