Hi QnAnxious
I am Dave, I will help you with this.
Windows updates use a file sharing process to move updates aroud the world much faster than if all updates cam from Microsoft servers.
Delivery Optimization is the process that allows packets of updates files to be downloaded to your PC form PC's all over the world and also to allow your PC to upload those parts of updates to other PC's
I have never heard of the Delivery Optimization service ever causing a PC to become infected, I presume there is a security protocol on that service to protect the uploading and onloading of ppdate files.