The Medical Minute: Influenza season

December 08, 2004

By John Messmer
Penn State Milton S. Hershey Medical Center
Penn State College of Medicine

Early this fall, every medical column including the Medical Minute recommended a flu shot to reduce the risk of catching influenza. Unfortunately, many people could not be immunized against the flu due to an inadequate supply. There are things can be done to avoid the flu or lessen its effects even if someone has not been immunized.

Many people use the term "the flu" for any unpleasant illness. It is important to understand that influenza is very different from and more serious than other viruses. The viruses that cause colds are milder than the flu. With a cold, individuals would rather be in bed; with the flu, individuals cannot get out of bed. With a cold, fever is usually less than 101 degrees. The flu typically has fever of more than 102 degrees. The flu hits hard and fast. Individuals feel very ill the first day with a very bad headache and intense body aches and very sore throat. Usually there is a persistent, hacking cough. Runny nose, congestion and sneezing are mild or not present. Compare that to a typical cold, which has more sneezing, runny nose and congestion and a scratchy throat. Colds come on slowly over a day or two -- a person may not feel very sick at first. With the flu, illness is sudden.

Do not confuse the two. Treatment of colds may reduce the symptoms. However, the flu has treatment that can stop the illness. The catch is, treatment works best if it is begun soon after the flu hits.

As with many illnesses, prevention is better than treatment. From contact with people and objects individuals contaminate their hands and bring the virus to their noses, eyes or mouths. Influenza virus is usually inhaled from the air. When infected individuals cough or sneeze, the virus-laden exhaled air travels up to three feet away from the source. The droplets remain suspended for a few minutes and can be inhaled by others. If infected people cover their mouths and noses and cough or sneeze into their hands, the viruses can then pass from one person's hand to another like cold viruses.

Incubation is about two days on average. Adults can spread the virus starting a day before they know they are ill and children shed virus for up to 10 days before symptoms begin. Infectiousness lasts about five days after the flu starts, but it is the fact that it can spread before a person seems ill that necessitates a set of universal precautions during flu season.

If individuals are ill, they should stay home if they can. If they must be in public, they should cough or sneeze into a tissue to keep the virus out of the air. If individuals cough into their hands, they should sanitize them with an alcohol-based gel or by vigorous washing for 30 seconds so the virus will not pass on. Individuals who are well should try to stay more than three feet from people who are coughing or sneezing. Throughout flu season, individuals should keep alcohol-based sanitizing gel near and never touch their eyes, nose or mouth unless they have washed or sanitized their hands. After shaking hands, sanitize them as soon as possible.

The new antiviral tissues are a small improvement over regular tissues. Their middle layer has a chemical that dissolves the outer coat of many types of virus and a weak acid to kill the uncoated virus. It takes about 15 minutes of exposure to the antiviral layer to kill viruses, so they are not a perfect defense. They are not a substitute for hand sanitizing, but might reduce virus spreading from tissue waste.

Influenza's greatest danger is secondary infections, typically pneumonia, but the severity of the flu itself can necessitate hospitalization in young children and the elderly. Maintaining general good health can reduce the risk of complications. That means proper nutrition, a reasonable amount of sleep and no smoking. All people over 65 and those over 50 with diabetes, lung or heart disease or reduced immunity for any reason can reduce their risk further with a vaccination against pneumonia caused by strep.

There is no cure for the common cold, but the flu can be treated. Having had a flu shot gives some protection, but it is not 100 percent. If an individual becomes ill suddenly with high fever, severe aches, headache, sore throat and severe weakness, usually all at the same time, he or she should try to see a doctor that day or the next. Most physicians make the diagnosis based on symptoms, since rapid testing has a substantial number of false negatives, accurate testing can take a couple of days and treatment must start soon to be effective.

There are two different classes of treatment for the flu: amantadine and ramantidine which treat only influenza A, or oseltamivir and zanamivir which work against influenza A and B. Some physicians do not prescribe these drugs because the studies show only a one- to two-day reduction in symptoms. A statistical reduction in symptoms can be deceiving, however. Although the duration of symptoms may be only slightly shorter, individuals likely will feel better much sooner and will stop spreading the virus sooner with treatment.

The medications can have side effects in some people, particularly amantadine and ramantidine that can cause confusion, irritability, nausea, nervousness and rarely, seizures. Oseltamivir is inhaled and could provoke wheezing in asthmatics. Cost can range from about $20 for amantadine to about $75 for oseltamivir and zanamivir. Another good use of these drugs is preventive treatment for close contacts of someone with influenza, although cost and occasional side effects may be an issue.

Flu season is here, but with a few precautions and some preventive measures, individuals can get through it in good shape. For more information, visit the Centers for Disease Control and Prevention Web site at

(Media Contacts)

Last Updated March 19, 2009