The flu, or influenza, is a viral disease of the respiratory tract—the nose, throat, bronchial tubes and lungs—and is highly contagious. It is spread though airborne droplets of moisture produced by coughs or sneezes. When you breathe these germs in through your nose or mouth, you may come down with the flu, generally within one to three days of exposure.
According to the U.S. Centers for Disease Control and Prevention (CDC) every year about five to 20 percent of the U.S. population gets the flu, although rates vary among age groups and from season to season. Outbreaks frequently start in school-age children, who carry the virus home and spread it to other groups.
Influenza is a serious illness. On average, approximately 36,000 Americans die from the flu and related complications each year and more than 200,000 people are hospitalized with flu-related complications, according to the CDC. Older people are more susceptible to flu complications, as are children, people with compromised immune systems and those with chronic illnesses such as heart disease, kidney disease and diabetes.
The most serious, often life-threatening complication of the flu is pneumonia. Other complications include ear infection, bronchitis, dehydration and worsening of chronic conditions, such as congestive heart failure, asthma or diabetes. Croup and a lung disease called bronchiolitis can also arise as complications in infants and young children.
In addition, the severity of illness is increased by exposure to cigarette smoke, which can injure airways and damage the cilia, the tiny hair-like structures that help keep airways clear. Toxic fumes, industrial smoke and other air pollutants are also risk factors.
There is also evidence that influenza can be more dangerous for women in their second or third trimester of pregnancy. The strain and stress of pregnancy on a woman's lungs, combined with the type of influenza, can lead to pulmonary problems, although there doesn't appear to be any danger to the fetus from the influenza virus itself.
There are three strains of the flu virus:
Type A results in severe illness that easily spreads throughout a population, even globally, affecting a large number of people at the same time.
Type B is a generally less severe strain that tends to affect fewer people.
Type C causes very mild symptoms, so mild that many people don't even realize they're sick.
The influenza virus changes its genetic makeup every year. That's why you can get the flu every year and why a flu vaccine containing the new virus is recommended annually.
This constantly changing virus presents a particular challenge to medical science, making it impossible to create a single vaccine to prevent the disease. Instead, the World Health Organization (WHO) and the CDC monitor each new strain of influenza virus as it appears, assessing which may be the predominant virus in the following year's flu season. Scientists use this data, collected by a surveillance network, to develop a vaccine each year against the specific virus they predict will predominate.
Drugs called neuraminidase inhibitors (NAI)—also referred to as antivirals—attack the influenza virus at its cellular level and block the virus's ability to escape from cells already infected, thus preventing the infection from spreading.
These antiviral medications can also prevent the flu, which can help contain the virus in certain settings, such as family members passing the flu to one another in a household, or coworkers spreading it in the workplace.
According to the U.S. Centers for Disease Control and Prevention (CDC) every year about five to 20 percent of the U.S. population gets the flu, although rates vary among age groups and from season to season. Outbreaks frequently start in school-age children, who carry the virus home and spread it to other groups.
Influenza is a serious illness. On average, approximately 36,000 Americans die from the flu and related complications each year and more than 200,000 people are hospitalized with flu-related complications, according to the CDC. Older people are more susceptible to flu complications, as are children, people with compromised immune systems and those with chronic illnesses such as heart disease, kidney disease and diabetes.
The most serious, often life-threatening complication of the flu is pneumonia. Other complications include ear infection, bronchitis, dehydration and worsening of chronic conditions, such as congestive heart failure, asthma or diabetes. Croup and a lung disease called bronchiolitis can also arise as complications in infants and young children.
In addition, the severity of illness is increased by exposure to cigarette smoke, which can injure airways and damage the cilia, the tiny hair-like structures that help keep airways clear. Toxic fumes, industrial smoke and other air pollutants are also risk factors.
There is also evidence that influenza can be more dangerous for women in their second or third trimester of pregnancy. The strain and stress of pregnancy on a woman's lungs, combined with the type of influenza, can lead to pulmonary problems, although there doesn't appear to be any danger to the fetus from the influenza virus itself.
There are three strains of the flu virus:
Type A results in severe illness that easily spreads throughout a population, even globally, affecting a large number of people at the same time.
Type B is a generally less severe strain that tends to affect fewer people.
Type C causes very mild symptoms, so mild that many people don't even realize they're sick.
The influenza virus changes its genetic makeup every year. That's why you can get the flu every year and why a flu vaccine containing the new virus is recommended annually.
This constantly changing virus presents a particular challenge to medical science, making it impossible to create a single vaccine to prevent the disease. Instead, the World Health Organization (WHO) and the CDC monitor each new strain of influenza virus as it appears, assessing which may be the predominant virus in the following year's flu season. Scientists use this data, collected by a surveillance network, to develop a vaccine each year against the specific virus they predict will predominate.
Drugs called neuraminidase inhibitors (NAI)—also referred to as antivirals—attack the influenza virus at its cellular level and block the virus's ability to escape from cells already infected, thus preventing the infection from spreading.
These antiviral medications can also prevent the flu, which can help contain the virus in certain settings, such as family members passing the flu to one another in a household, or coworkers spreading it in the workplace.
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