For many folks in America, getting flu shots is a rite that comes with the arrival of fall. You may have some questions about what the shot is, how effective it might be, why it has to be administered annually and who shouldn't get it. Let's take a look at those concerns and how they might apply to you.
What Exactly is the Shot?
While we tend to talk about the shot as if it were a single vaccine that's given to everybody, there are multiple versions. For example, adults over the age of 65 are frequently given a version that's designed to boost their immune response when confronted with the flu virus. Similarly, there is a vaccine that can be administered by nasal spray for certain people.
Each year, the federal government tries to anticipate what form of flu is likely to break out. When they identify strains that are spreading in late summer and early fall, this information and samples are passed along to factories that produce vaccines. A version of the virus is grown during the manufacturing process, and then it is administered in a dose intended to be too weak to cause the disease.
Why Are Annual Shots Necessary?
The flu virus changes rapidly as it comes into contact with different people and even animals. Consequently, there is almost always a different version of the flu in circulation each year. To keep pace with these changes, the government and vaccine manufacturers have to adjust what version of the virus they're vaccinating against.
How Effective Are Flu Shots?
The changing nature of the flu virus means that each year's vaccine will have a different level of effectiveness. A study commissioned by the CDC indicated that the highest effectiveness was in the 2010–11 flu season, at 60%. The worst effectiveness was in 2014–15, at 19%. In most years, effectiveness was above 40%.
That may not sound like great odds, but a 2 in 5 chance of avoiding misery is still worth it. 40% effectiveness also means that there are 40% fewer potential people spreading the disease, and that contributes to shortening flu season nationally.
Who Shouldn't Get the Shot?
Children under the age of 6 months are never given flu shots. Anyone with an egg or gelatin allergy may need a special shot due to the way vaccines are made. Talk to your doctor about your immune situation before getting a flu shot.