Hola Doug,

salud and sanidad both mean health, but they are used in different contexts: salud is normally used to refer to "people's health/wellbeing" and sanidad is normally used to refer to the "services offered by doctors and professionals in the sector", so, we could say that "si hay un buen servicio de sanidad, la salud de las personas será buena". In other words, sanidad is used more to refer to institutions/services" and salud is used to refer to "individuals". 

I hope this clarified it.

Saludos

Inma