Colds and flu are common infections, especially during the winter months. These infections share many of the same features. Both are caused by viruses, are highly contagious and involve the respiratory tract. Because of these similarities, the terms "the flu" and "a cold" are often used interchangeably. However, there are important differences between these two types of infection.

What is a "cold"?

A cold is a minor infection of the nose and throat that usually lasts from a few days up to a few weeks. Most of the time, a common cold is caused by a specific virus called a RHINOVIRUS. Over 100 different varieties of rhinovirus are responsible for colds so it is unlikely that a vaccine will ever be developed to prevent the common cold. The average adult has 2-4 colds per year while a young child may have 6-8 colds per year.

How do you catch a "cold"?

Although you can get a cold by breathing in the air around a person infected with the cold virus after that person sneezes, the most common way to get the virus is by direct contact. That is, a person with a cold may sneeze into his hand, then touch a doorknob. Shortly thereafter, you come by and grab the same door handle. You then touch your hand to your face and nose and the virus enters your nose and causes a cold.

Can a "cold" be prevented?

Because there are so many different variants of the rhinovirus, and because other viruses also cause the common cold, no vaccine is available to prevent the common cold. Furthermore, because these viruses are so prevalent, it is almost impossible to prevent a common cold. Nevertheless. There a few things you can do to decrease your chances of getting a "cold":

What is the "flu"?

This term really refers to an infection caused by the INFLUENZA virus. Three major variants of this virus exist (Types A, B and C; type C rarely causes influenza in humans). The "flu season" usually begins in late December or early January and it usually lasts through March. The symptoms of the "flu" are generally more severe than the "common cold". Influenza virus usually causes an illness of fairly sudden onset and the main symptoms include high fever, headache, muscle aches and fatigue. Cough, runny nose and sore throat can occur with influenza but these symptoms are not as prominent as they are in the common cold.

Can influenza be prevented?

YES! YES! YES!

The best way to prevent influenza is to receive the influenza vaccine every year in October or November. The influenza virus changes from year to year. Therefore, any immunity you might have from having the "flu" this year will not protect you from getting the "flu" next year. Each spring, experts in infectious diseases decide what are the most likely influenza viruses for the upcoming season (which is almost a year away). These infectious disease experts use information from viral cultures obtained from all over the world (especially from the Southern hemisphere where it is winter when we have summer) from people sick with influenza and then they try to predict the strains of influenza virus that will be prevalent in the upcoming season. As you might imagine, the experts are not always right. If they pick strains of influenza virus to include in the vaccine that do not turn out to be the common strains in the upcoming season, the influenza vaccine will not prevent you from getting the flu. Fortunately, the experts are usually right and they do a good job at creating an effective influenza vaccine. Nevertheless, you should remember that the influenza vaccine is not foolproof and you still may get the "flu" even if you received the influenza vaccine.

Who should get the influenza vaccine?

Basically, anyone who wants to lessen their risk of getting the "flu" should receive the influenza vaccine. However, certain groups of people are at much higher risk of potentially life-threatening complications from influenza and these people should be strongly encouraged to get the vaccine:

What about antibiotics?

Some people cannot take the influenza vaccine (egg allergy, other reasons). If you get the "flu", antibiotics will not help. Antibiotics treat bacterial infections, not viral infections. Both the common cold and influenza are caused by viruses. However, recently there have been some major improvements in the availability of anti-viral drugs. There are two main categories of anti-viral drugs used in the treatment of influenza.

M-2 inhibitors:

This class includes Amantidine and Rimantidine. These anti-viral drugs are only effective against influenza A. Their side effects include nervousness, lightheadedness and anxiety.

Neuraminidase inhibitors:

This class of drugs include Zanamivir and Oseltamivir. They are effective against both influenza A and B. The main drawback to these drugs are the cost.

Both the M-2 inhibitors and the neuraminidase inhibitors need to be started within 48 hours of the onset of symptoms, and there is evidence that the sooner these drugs are started, the better are the results.

Conclusion:

Influenza is a potentially serious disease that can usually be prevented. If you do get the "flu", there are drugs that can help hasten your recovery but they need to be started early.

The common cold is caused by a virus other than the influenza virus and the common cold rarely has serious consequences.