From what I understand so far about this prophecy, a plague of unknown origins (although, from everything I see, it'll be of divine origin) that will strike the wicked, the ungodly, the evil, and the corrupt, but specifically among them, those who are blatantly, and defiantly unrepentant. It will be very targeted, and not contagious (at least that's what I take from this), but it will be 100% deadly to any who catch it. The disease will rot their interiors, and produce boils, and lesions, and other nasty visible signs that it's there. Everyone who catches it will die, period.
On the flipside, this disease will not touch ANY believers in Christ, nor anyone who is saved. It will not come near them. In other words, sick people won't be able to transmit it to healthy people as the disease will come directly from God as judgment against the wicked. Now, as for those who are unsaved, it's not clear if they are protected as well, and this only targets the most evil of men and women. That's kind of a fuzzy area. All I can say is that, if someone is firmly, and unwaveringly unrepentant, they will catch this disease, and it will take them out.
Small side note. No matter what medical science does to fight this disease, no cure will be found, which leads myself, and many others, to believe it will be entirely divine, and spiritual in nature, and not created by either nuclear, chemical, or biological sources, but will come from demons, angels, or both, who are sent to administer this plague to the blatantly unrepentant in this nation, and around the world. Also, PS, I don't think this prophecy is part of the Lesser and Greater Virus prophecy, but rather stands by itself as a distinct judgment all its own.
EDIT (2021-06-21): The first flickerings (via a mass wave of vaccine deaths, and a number of other plagues) of this prophecy are underway, so I'm moving this to "In progress" at this point.
(*Do you have a better description, or did you find an error? Please let me know.