The very few people to have survived rabies almost always have brain damage, sometimes reversible, usually not.
The level of antibodies in the blood to provide protection is not well understood, and there is insufficient data to know whether anyone has been exposed to the disease on a second or subsequent occasion.
There are quite large populations of people in West Africa who appear to have natural immunity to ebola, and ebola-specific antibodies are present in their bloodstream. Quite how this has happened is a mystery, as these populations occur in areas where there have never been ebola outbreaks. It does appear that survival of ebola may provide a degree of protection against subsequent infection.
