Underwriters Laboratory requires some sort of sheilding, although in some cases it is wire mesh rather than glass. (In case of "Non-passive Failure" - my favorite techno term, thanks to GE.) This covers 99% of North American instalations and equipment.
This UV scare has been going on for well over ten years. There was an experiment in Italy where they baked some hairless mice with unsheilded lamps. Gee, they developed skin problems. The press went wild....
***You get more UV walking to your car than from sitting under halogen lamps.***
Note to JS: As you noticed lighting is not cut and dried, there are many options and the best solution depends on the details of your situation. Energy, quality, dimming, start-up, first costs, space, style, your age!, type of work....
Good Luck