How can I get rid of the viruses in my USB?

My USB just got viruses for no reason. I scanned it with Avira Antivirus and it detected some worms and deleted them. But the thing is, the worms just kept coming back. I scanned the USB repeatedly and each time was the same amount of viruses and they were all the same. The viruses made my Avira go crazy with virus detection, and all my files have been turned into shortcut files. I don’t want to format my USB because there are some important files I need to save. Is there any way I can completely kill the viruses?