INFLUENZA: What You Should Know
By James A. Wilde, MD, FAAP
Assistant Professor of Emergency Medicine and Pediatrics
Medical College of Georgia

February 22, 2002

Winter is here, and so is the flu season. What is the flu? What causes it? What are the symptoms? How can it be differentiated from a cold? What can be done to treat it?

Flu is a respiratory infection caused by influenza virus. The two primary types of the virus are influenza A and influenza B. These viruses can change rapidly, and because of this change, neither prior infection with influenza nor vaccination provides adequate protection. This is why flu vaccine must be re-formulated yearly, and why yearly vaccination is recommended for those at high risk for complications from the flu. Influenza causes an estimated 20,000 deaths in the United States each year, 90 percent of which occur in patients over 65.

The time between exposure to a virus and clinical symptoms is the incubation period. The shorter the incubation period, the more rapidly an infection tends to spread. Influenza is highly contagious and has an incubation period of three to five days, leading to explosive epidemics. Flu tends to arrive abruptly each winter, causes severe illness for six to ten weeks, and then disappears just as abruptly.

The primary symptoms of flu are cough, sore throat, nasal congestion and fever. Associated symptoms include headache, muscle aches, fatigue, chills, loss of appetite and particularly in children some degree of vomiting. There is a large degree of overlap in the symptoms of flu and colds but the primary difference is in the severity of the illness. People with colds tend to be uncomfortable, particularly if they have a fever, but they can still function.

People with true influenza infection tend to be much sicker, and often describe the experience as like being run over by a truck. Many people with the flu may be bedridden for several days. Fever tends to last longer with influenza infections than with colds, usually subsiding after three to seven days.

Adults with cough and fever during the flu season are highly likely to be infected by influenza. Children with cough and fever during the flu season are also likely to be infected by influenza. However, the clinical diagnosis of influenza is not as certain as it is in adults because many other respiratory viruses circulate in the winter and can cause the same symptoms. These other viruses only rarely cause fever in adults. Therapy in otherwise healthy people does not differ substantially between influenza infection and infection by other respiratory viruses, so laboratory tests usually are not required to make a specific diagnosis.

To treat the flu, take Tylenol or Advil for fever and muscle aches, sore throat lozenges to soothe the throat and any over-the-counter cold medication to relieve the congestion and stuffiness. Studies have shown that cough and cold medications are not effective for children less than 3 years of age so many pediatricians do not recommend them. For these children, only fever medications and time will help. Antibiotics are useless against influenza because antibiotics kill only bacteria. Taking antibiotics for uncomplicated flu may even be harmful because it can lead to the development of resistant bacteria. Antibiotics also do not prevent complications, so their use is not recommended.

Several antiviral medications are available to treat influenza but their effectiveness is limited. Research has shown that they reduce the duration of the symptoms by only one day. They are also quite expensive. For all these reasons they are not widely used except in high-risk patients.

Fever should dissipate in five to seven days, but cough and congestion may continue for two weeks or longer. If the fever persists beyond the expected range, if the patient becomes short of breath or develops chest pain, or if the respiratory symptoms are worsening at a time when they should be improving, then a secondary bacterial pneumonia may have developed. This is a situation where a visit to the doctor and antibiotics may be helpful. An otherwise healthy person with flu-like symptoms does not require medical attention unless symptoms are unusual or persistent. Several days at home in bed with over-the-counter medications will suffice. High-risk patients should seek care from their doctor if they suspect they have the flu. These same high-risk people should also be sure to get their flu shot prior to the flu season so they can prevent the infection.

MCG HealthCare is the health system of the Medical College of Georgia and is comprised of MCG Health, Inc. and the clinical services offered by the faculty of the School of Medicine and the members of the Physicians Practice Group. MCG Health, Inc. is a not-for-profit corporation operating the MCG Hospitals and Clinics, Children's Medical Center, the Georgia Radiation Therapy Center and related clinical facilities and services. MCG Health, Inc. was formed to support the research and education mission of the Medical College of Georgia and to build the economic growth of the CSRA, the state of Georgia and the Southeast by offering the highest level of primary and specialty health care.

For more information, contact:
Steven Padgett
Media Relations Manager
MCG Health, Inc.
(706) 721-9566