Immune Deficiency
Due to cancer, immunosuppressive drugs, or an illness that affects the immune system, some people might develop an immune deficiency. This makes their bodies more prone to a mumps infection even when they had been vaccinated and immune to the previous infection. In other words, an immune deficiency might prevent the live vaccine from activating immunity. However, this is not a common situation. Consult your healthcare provider to determine whether it is necessary to be revaccinated. [4]
