Vaccines such as the measles, mumps, and rubella (MMR), and varicella (MMRV), are recommended around the world and are based on the scientific principle of how they prevent and protect individuals against infection. It has been shown that these vaccines reduce both morbidity and mortality in both high- and low-income countries. MMRV are considered typical childhood infections with a good prognosis. However, they are highly contagious and can lead to serious complications. As individuals age, the risk of complications increases but have proven to be effective overall. Vaccination remains one of the most effective and safest interventions available to the public for primary prevention of infectious disease. Immunity, both direct and indirect, is induced in individuals vaccinated and can create herd immunity among populations. A variety of laboratory tests may be performed depending on the reason for the test and/or the presentation of signs and symptoms of measles, mumps, rubella, or varicella.