Comodo only detects Eicar as a virus if you use internet explorer! if you access the eicar webpage using firefox Comodo fails to detect Eicar.
http:// eicar.org/download/eicar.com.txt
Hello Aikno,
txt files are harmless, and if it’s not on your PC or RAM it cannot harm your PC thus CAV didn’t detect it.
If you download the .com version it will be detected via AV or Sandbox
https:// secure.eicar.org/eicar.com
Kind Regards
As Jacob said, nothing to worry about.
The Eicar site explains that the only reason there are .txt versions on the site is if you have trouble downloading the .com files. You are supposed to download the .txt file and rename the extension to .com.