In 2044, Yawgmoth expressed his difficulty in understanding why anyone would reject Plan A's HIV infection.
Because a person, regardless of whether they chose Plan A "HIV infection," Plan B's "drug and radiation destruction," or the then-undeveloped "189:3 Potion to reverse the immune system lifecycle" during the "immune system goes offline" stage, would have to face the Virus cocktail in the second stage of "gene implantation."
And within the Virus cocktail, there must be "its prototype," a substance with a mortality rate far higher than that of HIV, namely rabies (improved version).
Different viruses have different affinities for different cells.
The rabies virus is a neurophilic virus. It has extremely strong neural affinity, typically bypassing blood circulation and violently invading the brain through retrograde neural transport.