A VPN is defined more by what it does than what it is. What a VPN does is simulate a dedicated network over an open network. VPNs ensure that only authorized users can access the network and that the data cannot be intercepted. Security features differ from product to product, but most VPNs include encryption, strong authentication of remote users or hosts, and a way to hide the VPN from potential attackers. What solution will work best for your organization will be determined by your risks, needs, vulnerabilities and budget.
Consents are general in nature.
Providers are permitted to refuse care for those who do not consent. Authorizations are specific in nature. Providers are not permitted to refuse care for those who do not authorize. While providers will be dealing with consents, all covered entities must examine their business practices to see if authorizations will be required. In particular, many marketing efforts will require prior authorization from the people they are focused on.