What is influenza?
The flu is a respiratory illness (it affects the nose, throat and lungs). It is caused by one of the influenza viruses. The flu affects people every fall and winter – that’s why the time of year from November to April is known as “flu season.” The flu can cause mild illness or it can be serious. In some people, it can cause severe illness, lead to hospital care, or cause death.
Symptoms of the flu:
Who can get the flu?
Flu viruses can affect people of any age. Children are most likely to get sick because their immune systems aren’t strong enough to fight off the infection.
How the flu spreads:
Germs can spread through the air when a person with the flu coughs or sneezes. Also, germs can be spread when someone touches a desk, doorknob or other surface that a person with the flu has touched.
How to prevent the flu:
Take steps to protect your health everyday:
Is the flu serious?
It is a myth that the flu is “no big deal.” In fact, each year in the United States, on average:
Who is at risk for serious illness or flu-related complications?
Most healthy people who get the flu will get better without problems. However, many people are at high risk for serious complications, such as:
Complications can be serious, such as:
There are three types of flu viruses: A, B and C. The A and B viruses cause epidemics (widespread outbreaks in a country) of infection in people every year in the United States.
Flu viruses change from year to year, so that is why a new flu vaccine must be made each year to protect against the newer viruses. The 2010-2011 seasonal influenza vaccine includes protection against three flu viruses, an H3N2 virus, an influenza B virus and the H1N1 virus that caused so much illness last season.
What is a flu pandemic?
A flu pandemic is different from the regular flu season. A pandemic is an outbreak of a new flu virus – one that people have little or no immunity to.
Since flu viruses are constantly changing, a flu pandemic can happen if three conditions are met:
In 2009, the H1N1 flu virus met all three conditions and caused a worldwide outbreak. In late spring 2009, the World Health Organization declared that a H1N1 flu pandemic was underway. Over a year later, on August 10, 2010, the World Health Organization declared that the world was in a post-pandemic stage.
This year, the H1N1 virus is still contagious and will circulate during the regular flu season. However, for the 2010-2011 flu season, the flu vaccine includes protection against the 2009 H1N1 virus, plus two other flu viruses.
What is the difference between a cold and the flu?
The flu and the common cold are both respiratory illnesses, but different viruses cause them. They have similar symptoms (such as fever and sore throat), so sometimes it is hard to tell the difference. Here are some differences:
The Common Cold
More information on the Fight the Flu web pages