Better known as flu, an acute infection, that frequently occurs in epidemics or occasionally in world-wide outbreaks known as pandemics. Three types of influenza virus, known simply as types A, B, and C, have been identified; A and B are responsible for nearly all epidemics. Unfortunately, each of the three types has a number of different strains, and the virus undergoes subtle biochemical changes on an ongoing basis. As a result, someone who catches the flu or is vaccinated this year usually will not be immune during next year’s out-break. That is why those who need flu shots must get anew one each year. Influenza is typically seen in the United States and Canada in the fall and winter, usually involving strains that have been identified a few months earlier in Asia. These outbreaks develop quickly, spread rapidly, and may involve sizable numbers of people in a given community. While complications and mortality are uncommon in healthy individuals, influenza can be serious for children who have chronic illnesses.
Influenza is characterized by the sudden onset of chills, fever, muscle aches, headache, lack of appetite, and a dry cough. Nausea, vomiting, and abdominal pain some-times occur in younger children but are less common in adolescents or adults. (Acute gastroenteritis, often called stomach flu, is an entirely different type of infection.) In some children, influenza can appear to be a simple respiratory-tract infection or an illness with fever but without any cold or cough. Influenza does not cause a rash or intense inflammation of the throat (pharyngitis). If bacteria become involved as secondary invaders, complications such as bronchitis, sinusitis, middle-ear infection, and pneumonia could develop. Flu is spread via respiratory secretions that become airborne with coughing or are passed person to person by unwashed hands. A child or adult is most contagious for a period extending from 24 hours before the onset of symptoms through the time they show signs of resolving. The incubation period (the time from exposure to onset of symptoms) is one to three days.
Treatment of influenza is usually focused on relief of symptoms. Acetaminophen (Tylenol and other brands) or ibuprofen (Children’s Motrin and other brands) can be used to relieve fever and aches, but aspirin should be completely avoided because of the risk of Reye’s syndrome. The child should drink a lot of fluids. (There is usually not much appetite for solids until symptoms begin to abate.) Until the fever, aches, and cough have calmed down for 24 hours, the child should remain at home and quiet. Antibiotics will have no effect on the course of the illness, although they can be helpful if secondary bacterial infections develop.
Two drugs, amantadine and rimantadine, may reduce the severity of symptoms if given within the first 48hours of the onset of a type A influenza virus infection. (The type of virus involved in a local epidemic may be identified by the local health department.) They can also prevent influenza from spreading to other family members. These drugs are not routinely given to children, since influenza normally resolves without treatment in two to five days. Your child’s doctor can advise you whether one of these medications might be helpful or necessary.
A flu vaccine is developed each year and given every fall. It is not recommended for all children but should be considered annually for those with chronic conditions such as heart disease, asthma, kidney failure, and disorders of the immune system. For children with these and other long-term medical problems, influenza can be a much more serious (or even fatal) illness. Other family members in the home of a high-risk child should be vaccinated as well. Flu vaccine can be given to infants as young as six months of age, although it is less effective its younger children.
Some parents may choose to vaccinate children who do not have chronic illnesses to minimize the risk of their missing school or other important activities.