Vaccine

A vaccine (also known as vaccination, immunization, or jab) is when your body is given a modified version of a virus or bacteria so that your immune system can develop immunity against it without getting the harmful illness associated with it. This is usually in the form of a small injection and is why it is also known as a "jab" and tends to be given into the muscle in your upper arm.

Vaccines have been key in preventing serious and potentially fatal infectious diseases. There are also seasonal vaccines, such as the flu vaccine and travel vaccines, that you will only require if you are traveling to certain places abroad where some diseases are more prevalent than in the US. There are also specific vaccines, such as hepatitis, depending on your risks of exposure to blood-borne viruses.

The bacteria or viruses are made safe for a vaccine by either weakening, changing, or killing them so that they cannot cause harm. If a vaccine uses a weakened version of the pathogen (virus or bacteria), then it should be considered whether it is safe to give to people with a lowered immune system.

All approved and licensed vaccines have gone through clinical trials, meaning that they have been thoroughly tested and are safe for use. The side effects of vaccines are usually mild and short-lived; however, in a very small number of people, a severe allergic reaction can occur, known as anaphylaxis. It is not common, but it is life-threatening. It can develop quickly, causing the swelling of airways and difficulty breathing along with other symptoms such as feeling faint or dizzy, feeling sick, and collapsing. Any signs of anaphylaxis should be responded to by calling 911 immediately.