Flu's Clues

The Disease

Once again flu season is upon us and it is time to prepare for this years epidemic. During the influenza season, all it takes is one person infected with influenza to trigger an outbreak. In the U.S., these outbreaks usually occur between November and April. They erupt quickly in different regions and spread out in an ever - widening geographic circle for 2 to 3 weeks. The influenza virus is spread predominantly by sneezing, coughing, and even talking.

The Symptoms

Once the virus has been absorbed in the respiratory tract it begins to replicate. The incubation period-from initial exposure to onset of symptoms and/or virus shedding-lasts between 18-72 hours. At this point, initial signs and symptoms of influenza, such as the sudden onset of fever, cough, and aches, begin to appear throughout the body. This usually indicates that the symptoms have become constitutional and are not limited to the respiratory tract. This period lasts about 5 to 10 days, at which point the infection has run its course, and the virus is no longer detectable in the body.

Each year, the influenza viruses mutate to change their outer surfaces, which leaves us vulnerable to catching the flu repeatedly. Each year on average in the U.S. influenza accounts for 20,000 to 40,000 deaths, and more than 300,000 hospitalizations. Most flu related hospitalizations are due to respiratory complications-the majority of which are seen in adults over 65 years. Flu related complications can occur at any age; however, the elderly and people with chronic health problems are much more likely to develop serious complications after influenza infection than are younger, healthier people.


Currently, vaccination is the primary preventive measure for influenza. For older folks, and those with chronic diseases, getting a flu shot may be the single most important thing they can do to stay well. Like last year, the CDC expects some delays in availability of flu vaccine supplies this season. However, it is projected that the total influenza vaccine supply for the 2001-2002 season is expected to increase over last season. During each month of the influenza season there should be a larger supply than was available last year. Further, projected delays in distribution are not expected to be as great as those experienced last season. New developments in the influenza vaccine supply status will be published as they become available. The use of antiviral drugs amantadine and rimantadine in the elderly and other high-risk people may also be considered. These compounds have been shown to be effective in preventing illness when taken throughout the period of exposure to virus during the flu season. They can also reduce the severity and duration of illness when taken early after the appearance of symptoms.

Source: Roche Pharmaceuticals,