Understanding Measles Measles is not just a childhood disease; it is a highly contagious viral infection that can result in serious health complications, such as pneumonia, encephalitis, and even death. Measles is caused by a virus that spreads through respiratory droplets when an infected person coughs, sneezes, or talks. This virus can remain active on surfaces for up to two hours, making it extremely contagious. Measles is contagious 4-5 days prior to symptoms developing a