Type Windows Security in the taskbar search window.
From there you should see this window:
Click on Virus & Threat protection and another windows should pop up with:
Then you can click on manage settings and the last window should appear:
Make sure that Real-time protection is turned and that should allow the Vanta Agent to report back with Anti Virus turned on!
If you run into any issues please feel free to reach out to support@vanta.com!