As a rule, it is prudent to provide workers with the minimum level of computer access needed to complete their tasks, and the ability to add or change programs should only be provided to authorized personnel. The effective use of antivirus software is an essential component of computer security. However, its use must be monitored to assure that employees are conducting checks regularly. I often encounter infected systems that included a first-rate antivirus program, but the automated scan routines were deactivated because they interfered with work. As well, this software must be updated because new viruses are always being released and existing ones are being modified to elude detection.
Updates are usually available free over the Internet.
Development of a back-up routine is the most effective countermeasure against a variety of threats, including viruses. Mission-critical data such as the electronic patient record must be backed up daily. Many viruses remain dormant before an infection is discovered, and this means the back-up file may be infected as well. Never use an infected backup to restore a system. Since viruses spread when information is communicated or transported between computers, an effective countermeasure is to isolate critical systems from potential threats.