A fairly common practice is being followed in the construction of this metaphorical use of désert médicale. The word désert is being used to denote any place completely lacking something. So the Larousse dictionnaire Francaise gives a metaphorical use of désert thus:
used for a place to be deserted, uninhabited: an empty or little frequented place : * les bureaux vers midi c’est le désert* (difficult to render the expression exactly: "The offices towards midday, it's desert.")
However, it is close enough to see that the use of désert as a metaphor for the absence of something is well-established and wide enough to embrace the absence of medical facilities.
English is no less fitted to the use of metaphor than is French. Merriam Webster gives the metaphorical use of the word desert as one of its definitions (entry 3 of four).
A desolate or forbidding area.
example: lost in a desert of doubt
This is not exactly the use cited by Marion, but it is in the right direction.
The Cambridge English dictionary gets much closer in its examples.
A cultural, intellectual, etc. desert (disapproving).
example: This town is a cultural desert.
The etcetera in the Cambridge definition seems to me to establish clearly enough that anglophones would have no difficulty in understanding any reasonable extension of this metaphorical use of the word desert to any regrettable absence of something desirable, just as francophones do. Rural villages might from the closure of shops, schools, pubs etc, be said to have been turned into social deserts, and, from the closing down of rural bus services into desert islands.
So yes, certainly you can translate the expression into English.