Flu Season November 26, 2001
As winter approaches, medical experts make their annual predictions about how severe flu season will be and recommend that some Americans be inoculated with flu vaccine. About 95 million Americans will get the flu this year. Who is most at risk to come down with — or even die from — the flu?

Of course, it is difficult to give an accurate pre-season prediction on the timing and severity of a winter flu season. Slight changes in the strains of flu virus from year to year can cause better or worse flu seasons. But what is known with certainty is that flu outbreaks generally hit the United States between December and March, with the number of reported cases typically peaking in January and February. In preparation, vaccines are usually distributed in October, so that individuals at risk have plenty of time to build up antibodies before the flu germs arrive.

This year, for the second year in a row, the vaccines were delivered on the late side. U.S. health officials have urged healthy people to wait until December for a shot so that the elderly and those with chronic medical conditions can have the first round of vaccines. Health officials insist that vaccines supplies will be adequate and that anyone who wants an inoculation will receive one.

Even when there's enough flu vaccine to go around, only about 1/4 of Americans normally bother to get the vaccination. However, this isn't a normal year. This year there is a great deal of anxiety about anthrax. Initial reports warned that early symptoms of inhalation anthrax — fever, cough, muscle ache — would be similar to those of the flu. Now doctors and clinics are seeing many people looking to get a flu shot for the first time in their lives.

However, the Centers for Disease Control and Prevention (CDC) advises people to not confuse the issues of anthrax and flu immunization:

CDC does not recommend that you get a flu shot so you can tell if you have the flu or an anthrax- related illness. Many viruses and bacteria besides influenza (including anthrax) can begin with flu-like symptoms... In fact, most illnesses with flu-like symptoms are not caused by influenza or anthrax... You should get a flu shot to prevent the flu.

Influenza kills around 2000 Americans each flu season. So, just like every year, you or your relatives should get a flu shot if you or they are in one of the risk groups: people who are 65 years old or older; adults or children with chronic health conditions, such as asthma, diabetes, kidney disease, or an illness that lovers the immune system; health care workers; or anyone who takes care of or spends time around any of the people listed above.

Teaching the Problem
 Epidemics are outbreaks of infectious diseases that affect a disproportionately large number of individuals within a population, community, or region at the same time. Epidemiology is the branch of medical science that studies the transmission of disease in human populations. Instead of individuals, epidemiology looks at groups of people in an attempt to figure out how disease spreads and to identify populations at high risk for a specific disease. Epidemiologists rely heavily on statistics and mathematical analysis, looking especially at data from previous outbreaks of the same or similar diseases.

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Destination Math

  • Before moving on to the mathematics, you might want to have students review background information on influenza, such as Flu Facts from TeensHealth, and explore the human respiratory system in the Middle School Science Gateways activity, Anatomy of the Respiratory System.

  • Students can get a look at how math is used to study the spread of disease in the Matrix Analyzer activity, Catching the Flu. They will use a contact matrix to study the spread of flu by contact between people.

  • If students need more practice multiplying matrices, they can work the activity, Matrix Multiplication.
 Analyzing the Problem
  1. The contact matrix used in the above activity, Catching the Flu, tracks contact between groups of people, but does not weigh which individuals might be at higher risk to get sick if exposed to the flu. Ask students the following questions:

    • How does a contact matrix predict high risk groups for infectious diseases?

    • What other information would you use to determine what groups are at highest risk?
Grandma was Right!
 How many sitcoms and commercials have you seen where a person with a headcold is offered chicken soup? Well, researchers at the University of Nebraska Medical Center have found that chicken soup really does soothe cold symptoms. In laboratory tests, researchers found that chicken soup contains ingredients that act as natural anti-inflammatories and reduce the pain of sore throats. As if that weren't enough, chicken soup also seems to slow down the movement of the white cells called neutrophils that cause the mucous associated with coughs and runny noses. Researchers found no indication that noodles or matzo balls make any additional difference. But they couldn't hurt.

Beyond the Vaccine
Last year, the Food and Drug Administration (FDA) approved Tamiflu, a drug used to shorten flu patients' symptoms by about a day. Tamiflu is also effective at preventing flu, if taken daily during a flu outbreak.

Worse than Epidemic?
 When a disease spreads across much much of the globe and affects millions of people, it is no longer an epidemic. It is called a pandemic. The flu of 1918, which killed 20 million people worldwide, was just such a pandemic. Students can read more about how a flu outbreak can turn into a serious epidemic at PBS's The American Experience: Influenza 1918, or read the entire first chapter of Gina Kolata's book, Flu: The Story of the Great Influenza of 1918 posted online at CNN.com
Extending the Problem
  1. Students can learn more about the influenza with a public health slant at the following sites:

  2. For biology students, the following sites offer information on the structure of the flu virus, the different strains that cause the flu each year, the transmission of flu from bird to pig to human, and the genetic changes involved in creating a deadly new flu virus:

  3. There has been controversy in recent years over whether vaccines themselves pose a health risk. Students can learn more about vaccines at the following sites:

  4. There are several new developments in the field of vaccines:

    • Scientific American's "Edible Vaccines": One day children may get immunized by munching on foods instead of getting shots. Food vaccines might save millions who now die for lack of access to traditional inoculates.

    • Scientific American's "Genetic Vaccines": Vaccines made of genetic material, either DNA or RNA, have progressed from fanciful idea to early human trials.

  5. Students can learn more about epidemics and the work of an epidemiologist:

Related Activities
Introducing a Virus
In this simulation activity, students investigate the effects of a virus on a rabbit population.
Preparing for the Flu
This Riverdeep Current story examines some of the available flu treatments.