But there is some evidence tanning lamps can help fight or prevent flus as well...
Agreed. Lying under a tanning lamp causes your body to make Vitamin D — an excellent immune-system booster.
Tanning lamps emit mostly UV-A, which is the least-dangerous band of UV. OTOH, UV-C has a shorter wavelength, much more powerful photons, and will break apart DNA and RNA. That’s what makes UV-C an effective sterilizer — and dangerous to just about every living thing (and not-quite-living viruses). The lamps I’m expecting to receive soon come with a timer, a remote control, and a delayed start. You set the lamp up, stand near the doorway, press the start button on the remote, beat a hasty retreat, and shut the door behind you. As the lamps only sterilize what the light shines on, I’m getting two — so I can zap the room from two directions at once.