Can there be "an" "endemic"? (Can "endemic" legitimately be used as a noun?)

A recent AMA headline shouts: "The Resident Depression Endemic---and Solutions Underway".

Now, doctors are not known for their writing proficiency (self included here) but this seems to me to be a new or possibly just uninformed use of the word "endemic".

Probably this was a staffer who wasn't sure whether it was permissible to use the term "epidemic"...

Endemic as an adjective means regularly found in a specified population. Its use as noun means an endemic disease. The OED finds this usage from 1662 and quotes The Saturday Review (1859) for a figurative use thusly:

Snobbishness in an insidious endemic.

For a literal use, we may consult An outline of the history and cure of fever, endemic and contagious by R Jackson (1798)

... while contagious fever, occasionally exposed to pure air often intermits or remits like an endemic;....

The noun usage seems as dated as Jackson's medical advice though.

One more example by request, from Medical Record, Volume 35 (April 6, 1889), G F Shrady and T L Stedman eds.

Only within the last twenty years, after the attention of medical men had been drawn to repeated observations of endemics and epidemics of pneumonia,....