What is the flu?
The flu, or influenza, is caused by a virus. When the virus enters a human body it attaches to a host cell and uses the genetic material found there to replicate itself. The new particles detach from the host cell and quickly attack other cells. Bodily fluids such as mucus and saliva harbor these virus particles. When a person coughs or sneezes they release a spray of virus particles waiting to infect the next host cell they contact.
How do flu vaccines work?
The flu vaccine consists of an influenza virus grown in a chicken egg, extracted and then chemically treated to render it non-infective. Once administered (by injection or nasal-spray), it causes the immune system to develop antibodies against influenza virus particles. When the body is then exposed to the actual virus, the body has the necessary protections already in place.
At any given time, multiple strains of the flu virus may be circulating. The effectiveness of the flu vaccine depends in part upon the similarity of the viruses included in the vaccine to the viruses currently circulating in the population. Because of this, three kinds of flu virus are used to produce each year’s vaccine.
Want to know more?
The Centers for Disease Control and Prevention offer a wealth of information for those interested in learning more about the virus strains selected for vaccines and the strains anticipated to cause illness each flu season. Both the CDC and flu.gov monitor seasonal flu activity and provide up-to-date news and statistics.
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