Any pharmfags / medfags out there know why they are adding azithromycin to the hydroxychloroquine treatment?

I was always taught that antibiotics (like azithromycin) are ineffective against viruses. What am I missing here?

link is to the French study on this combination therapy

I didn't hear POTUS mention azithromycin being part of what they will start using in the U.S. but I assume they will take the advice of the Frogdocs and add it in there.

https://drive.google.com/file/d/186Bel9RqfsmEx55FDum4xY_IlWSHnGbj/view