When you are injected with the flu vaccine, your body reacts as if it has been infected with the actual living virus and makes antibodies that provide immunity against the real virus. These antibodies remain at high levels for only six to nine months. These waning antibody levels are one reason why you need to be revaccinated each year.
The main reason you should be revaccinated yearly is the flu virus is constantly changing and evolving into new strains. Each year the CDC attempts to predict which flu strain will be predominant. The CDC works with vaccine manufacturers to produce the specific vaccine that will combat the predicted strain.
If you are concerned about the cost of a flu immunization, check with your local health department for locations in your area where free flu shots are given.
Treating yourself at home
When you are exposed to the flu, the virus incubates for three to five days before symptoms begin. You probably have the flu if you come down with a high fever, sore throat, muscle aches, a runny or stuffy nose, and a cough (usually dry). The symptoms in children may also include vomiting, diarrhea and ear infections. Flu is usually self-treatable but has to run its course. You can treat symptoms by getting bed rest, drinking plenty of fluids, taking acetaminophen for aches and pains, and using a humidifier to keep nasal passages moist.
Expect the flu to last about five days, which is the time it takes your body to produce the antibodies that finally beat the infection. You will be protected from that strain of influenza for the rest of the season. Some people continue to feel ill and cough for more than two weeks. In some cases, the flu can make health conditions such as asthma or diabetes worse or lead to complications such as bacterial pneumonia. Adults older than 65 and people with chronic health conditions have the greatest risk for complications from the flu, the CDC says.
Antiviral medications are also recommended to treat the flu--amantadine, rimantadine, zanamivir and oseltamivir--but must be taken within the first two days of illness to be effective, the CDC says. They can reduce the length of time flu symptoms are present. These medications usually are used in hospitals, nursing homes and other institutions where people are at high risk for complications of the flu. Some side effects may result from taking these medications, such as nervousness, lightheadedness, or nausea. Individuals with asthma or chronic obstructive pulmonary disease are cautioned about using zanamivir. Talk to your health care provider if you think you should take one of these medications. These medications are not meant as a substitute for vaccination.