I'm sure there are, but, in a pre-scientific age, such accounts have a tendency to be rather unreliable. Where bubonic plague is primarily transmitted by flea

I'm sure there are, but, in a pre-scientific age, such accounts have a tendency to be rather unreliable. Where bubonic plague is primarily transmitted by flea bites, the plague doctor gear is ultimately a personal protective equipment version of the Maginot Line. But it would plausibly offer some protection against contracting pneumonic plague from getting coughed on all the time.