With the most severe influenza season in decades already underway, prevention and treatment of the flu virus are taking on a new urgency. But while vaccination remains the best way to prevent infection and complications associated with flu, as many as 40 million people will contract influenza this year.

"Getting vaccinated in December or later can still protect you against the flu and is particularly important for high-risk populations like children and the elderly," said Donald B. Perlman, MD, Director of the Allergy Clinic at Newark Beth Israel Medical Center. "With the severity of the flu this season, it's imperative that people who contract the disease see their doctor quickly to minimize the length and severity of their illness."

Many flu sufferers are unaware that antiviral medications can reduce the duration of the symptoms of influenza when started within the first two days experiencing flu symptoms. Tamiflu (oseltamivir phosphate), the only medication indicated to treat type A and B strains of influenza in adults and children over 1 year of age, is the most commonly prescribed influenza antiviral medication. Tamiflu can help patients feel better sooner (30 percent or 1.3 days faster) compared with placebo when taken within two days of symptom onset. Clinical trials have also shown Tamiflu to be up to 92 percent effective in preventing influenza illness in adolescents 13 years of age and older, adults and the elderly when taken once daily for at least seven days.

Children, Elderly at Greatest Risk

While most flu deaths occur among people age 65 and older, children younger than two years old are as likely as those over 65 to be hospitalized because of the flu. It is estimated that children are three times more likely to get sick with the flu -- on average, one in 10 adults is affected by influenza annually, compared with one in three children. Since young children can suffer between six to eight colds each year, they are sometimes misdiagnosed. This means that the infected child may not receive the proper treatment, staying ill for longer, spreading the virus to others and risking the development of complications.

Flu Signs and Symptoms

Both a cold and the flu are viral infections that cause similar symptoms such as coughing and sore throat. A cold is only a minor viral infection of the nose and throat, while the flu, on the other hand, is usually more severe. The onset of flu symptoms is often very sudden and is not confined to the respiratory tract. Common flu symptoms include sudden onset of fever and chills, cough, muscle pain, headache, fatigue and weakness. Some people also get a stuffy nose and sore throat. Flu suffers should visit their doctor within two days of the onset of symptoms for antiviral medications that can reduce the duration of influenza.

The Impact of the Flu

It is estimated that about 36,000 people die from influenza and its complications each year, while an average of 300,000 Americans are hospitalized. Current surveillance data indicates that people in the U.S. are getting sick with flu earlier in the year than usual. Laboratory tests from across the country indicate that a greater proportion of specimens testing positive for influenza are type A, which have historically been associated with more severe flu seasons during which higher numbers of influenza-related hospitalizations and deaths have occurred.

The influenza virus is highly contagious and is transmitted when droplets are shed by an infected person during sneezing or coughing. A person becomes infected by breathing in these droplets. The virus settles into the respiratory system, and begins replicating 24 hours before symptoms are discovered. An infected person can pass on the disease for four to five days and influenza may remain in a local area for up to six weeks. According to the Centers for Disease Control and Prevention, ten states reported widespread flu activity in late November, with nine additional states reporting regional activity. Flu season in the United States runs from November to April.

Flu Medication

Tamiflu, co-developed by Gilead Sciences, Inc, is a systemic treatment for the most common strains of influenza (types A and B). The medication targets one of the two major surface structures of the influenza virus, the neuraminidase protein. The neuraminidase site is virtually the same in the most common strains of influenza, types A and B. Tamiflu attacks the influenza virus and is thought to work by stopping it from spreading inside the body. Tamiflu treats flu at its source, by attacking the virus that causes the flu, rather than simply masking symptoms.

Tamiflu was approved by the U.S. Food and Drug Administration (FDA) for the treatment of uncomplicated acute illness due to influenza infection in adults in October 1999.