I have been using Linux (Mint right now) for about 3 years. As a typical former Windows user, I worried about viruses at first. While they are not unheard of in Linux, they seem to be rare. So far, I have had no need for antivitus on Linux; I always use a firewall and a router, and that seems to be sufficient.
There is the risk of viruses that target Windows finding their way onto your system, but they can't do anything on your Linux system. They can, however, be passed on to a Windows machine, if you share files with a Windows user. But this can be avoided by scanning the files you transfer with the antivirus on the Windows machine before opening them. I believe the built-in security program in Windows 10 (forget what its called) can easily be set to scan any USB device before opening the files on it.