Seasonal Influenza

What is seasonal influenza (flu)?

Seasonal influenza, commonly called "the flu," is caused by influenza viruses, which infect the respiratory tract (i.e., the nose, throat, lungs). Unlike many other viral respiratory infections, the flu can cause severe illness and life-threatening complications.

Last year, a new flu virus called 2009 H1N1 spread worldwide causing the first flu pandemic in more than 40 years. Experts expect the 2009 H1N1 virus to spread this upcoming season along with other seasonal flu viruses. The 2010-2011 flu vaccine will protect against 2009 H1N1 and two other influenza viruses.

What are the symptoms of the flu?

Influenza is a respiratory illness. People who have the flu often feel some or all of these symptoms:

  • Fever or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue
  • Vomiting and diarrhea which are more common in children than adults.

How does the flu spread?

The main way that influenza viruses are thought to spread is from person to person in respiratory droplets of coughs and sneezes. Called the "droplet spread," this form of transmission occurs when droplets from a cough or sneeze of an infected person are propelled (generally up to 3 feet) through the air and deposited on the mouth or nose of people nearby.

The viruses can also spread when a person touches respiratory droplets on another person or an object and then touches his own mouth or nose (or someone else's mouth or nose) before washing his hands.

If I got the flu last year, will I have immunity against the flu this year?

In general, a person who is infected with an influenza virus will have some immunity to closely related viruses that may persist for one or more years.

For example, if someone was infected with the 2009 H1N1 virus that predominated during the 2009-10 season, he is likely to have some immunity that will protect him if he is exposed to that strain or a closely related strain again during the 2010-11 season.

The degree of protection depends on the health of the person involved. Young and healthy people with normal immune systems will likely have good immunity against the same or closely related strains of virus from one year to the next. However, people with weakened immune systems are less likely to have immunity that carries over to other years.

What are the complications of the flu?

  • Bacterial pneumonia
  • Dehydration
  • Worsening of chronic medical conditions, such as congestive heart failure, asthma, or diabetes
  • Children may get sinus problems and ear infections
  • People who are 65 years and older are at greater risk of serious illness and death

How soon will I get sick if I am exposed to the flu?

Once a person is exposed to flu virus, the symptoms begin to show within one to four days, with an average of about two days.

How long is a person with flu virus contagious?

The period when an infected person is contagious depends on the age and health of the person. Studies show that most healthy adults may be able to infect others from 1 day prior to becoming sick and for 5-7 days after they first develop symptoms. Some young children and people with weakened immune systems may be contagious for longer than a week.

How can the flu be prevented?

The United States Centers for Disease Control and Prevention recommends flu vaccine as the first and most important step in preventing flu.

Antiviral drugs are a second line of defense against the flu. Antiviral drugs are prescription medicines (pills, liquid or an inhaled powder) that fight against the flu in your body. Antiviral drugs are not sold over-the-counter and are different from antibiotics. You can only get them if you have a prescription from your doctor or health care provider.

Do other respiratory viruses circulate during the flu season?

In addition to flu viruses, several other respiratory viruses also can circulate during the flu season and can cause symptoms and illness similar to those seen with flu infection. These non-flu viruses include rhinovirus (one cause of the "common cold") and respiratory syncytial virus (RSV), which is the most common cause of severe respiratory illness in young children, as well as a leading cause of death from respiratory illness in those aged 65 years and older.

For inquiries, call the University clinic at local 710 or direct line 536-0252.

Source: United States Centers for Disease Control and Prevention (CDC)