Subacute Sclerosing Panencephalitis (SSPE) is a rare, progressive neurological disorder caused by a persistent measles virus infection. It is not contagious in the traditional sense, as it cannot be directly transmitted from person to person. However, the initial measles infection that precedes SSPE is highly contagious. It is crucial to prevent measles through vaccination to minimize the risk of developing SSPE later in life.