They can still perform serious damage or they can cause hidden problems in your computer that will drive you nuts trying to figure out what is wrong with your computer. There are several ways to combat viruses transmitted thru email. One method is for the user to have antivirus software installed on the computer. This software checks each file the computer's hard drive accesses. That same software can check the email that user receives via a typical email client.
Some antivirus packages can even check the files a user downloads.
These software packages require updates in order to stay aware of the new viruses appearing each week. You're antivirus software is only useful if it is kept updated with those new virus patterns from the software developer. VCI's Answer VCI has an email filtering service called VirusWatch that checks each incoming email for the most common viruses. If that email has been determined to contain a virus that email is quarantined. It is then the sender's responsibility to remove the virus from their computer.