Explanation/Reference:
Explanation:
System health agent (SHA) is a NAP component.

System health agent (SHA)

A component that checks the state of the client computer to determine whether the settings monitored by the SHA are up-to-date and configured correctly. For example, the Windows Security Health Agent (WSHA) can monitor Windows Firewall, whether antivirus software is installed, enabled, and updated, whether antispyware software is installed, enabled, and updated, and whether Microsoft Update Services is enabled and the computer has the most recent security updates from Microsoft Update Services. There might also be SHAs (and corresponding system health validators) available from other companies that provide different functionality.
References:
http://technet.microsoft.com/en-us/library/cc731260.aspx