Available in the form of an injection (shot), the MMR vaccine (officially known as M-M-R® II) is given in order to prevent measles, mumps, and rubella. This immunization is typically given to children, first when a child is between 12 and 15 months old, and again right before the child starts elementary school. In some cases, MMR may also be recommended for an adult. The shots are typically administered in the upper arm, just under the skin.
MMR is a "live" vaccine. This means that it works by using living viruses that have been altered. However, the body's immune system still responds to the viruses, providing future protection from the diseases. In general, live vaccines provide better protection against infections, compared to other types of vaccines.
Although most people do not have any negative reactions to the shot, MMR side effects are possible. For example, in some cases, a person may have temporary joint pain or swelling after getting the injection. Fever and mild rash have also been reported after getting the vaccine.
(For a more in-depth look at this vaccine, click MMR. This article takes an in-depth look at what to discuss with your child's healthcare provider, when the MMR shot should be avoided, and more.)