Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.
Influenza is an acute infection caused by any of three types of viruses (A, B, or C). Type A strains are associated with the most severe disease. Many people confuse influenza or flu with the common cold. They are different. The common cold can be caused be a variety of viruses that infect the upper respiratory system (nose, mouth, throat). Flu is caused by several types of influenza virus and is usually more severe than a cold.
In 2009, a new type A strain emerged called H1N1. Because there was little immunity in the human population to the H1N1 strain, it had the ability to spread easily from person to person worldwide and sicken even more people than a usual seasonal strain. When this happens, it is called a pandemic. In July 2009, a worldwide pandemic of H1N1 was declared and is still in effect.
Flu is an acute infection of the airway tract in the nose and throat that can sometimes spread down into the lungs. Flu in adults is a frequent cause of acute respiratory illness. Flu, however, affects people of all ages. Children are among the groups most at risk for developing flu and its complications and are more likely to spread the infection to others.
Flu season (a sharp increase in reported cases) usually begins in late fall and early winter, and cases usually spread widely. The peak season for the flu in the northern hemisphere is from November through March though cases can be seen all year long.
Flu in Children Causes
The flu is caused by one of three types of influenza viruses. Types A and B are responsible for the yearly flu epidemics, and type C causes sporadic illness. Type A is further divided into different subtypes based on the chemical structure of the virus.
Is the Flu Contagious?
Influenza is highly contagious. The virus is spread when someone either inhales infected droplets in the air (coughed up or sneezed by an infected person) or when someone comes in direct contact with an infected person's secretions (for example, kissing, sharing of handkerchiefs and other items, and through use of objects such as spoons and forks).
Flu in Children Symptoms
Symptoms usually begin two to three days after exposure to the virus. The flu comes on quickly and attacks the upper respiratory system.
Classic symptoms include high-grade fever up to 104 F (40 C), chills, muscle aches, headaches, sore throat,
dry cough, and
malaise (just plain feeling sick). These symptoms usually last for
three to four days, but cough and tiredness may linger for one to two weeks after the fever has gone away. Other family members or close contacts often have a similar illness.
In younger children, the pattern of influenza may be a typical influenza-like illness or look like other respiratory tract infections such as croup, bronchitis, or pneumonia. Abdominal pain, vomiting, and diarrhea are frequently observed in children. Vomiting tends to be more significant than diarrhea. Fever is usually high, and irritability may be prominent.
In infants, the flu often goes unrecognized because the signs and symptoms are not specific and may suggest a bacterial infection. Influenza in infants younger than 6 months
of age is less common, but symptoms include lethargy, poor feeding, and poor circulation.
Complications from the flu include pneumonia, ear infections, sinus infections and may worsen asthma, heart failure, or diabetes.
Why are children at higher risk for getting the flu?
Children are more likely to get the flu or have flu-related complications because their immune systems are still developing. A recent CDC study shows that treating children with the flu can be costly. Each year in the U.S. an average of
20,000 children under the age of 5 are hospitalized for flu-related complications.