I don't say Iris as Eye-russ, and I don't say virus as Vie-riss. In the same way that I don't say "did" as "dud," "wrist" as "rust," or "dammit" as "dammut." The "rhyme" of Iris/virus is "one mile from home" - so close that it emphasizes the difference, for me.
Iris does not rhyme with Cyrus either. Cyrus the Virus would not be so lame imo, since that actually does rhyme.
I don't even think rhyme-teasing is a real problem with any decent name though. It's just something people list when we think of reasons we don't like a name.
- mirfak