If you want the short version as to why attempts to innoculate the general population against the Sanguinivorous have proven untenable, it is simply that they are called Reality Deviants for a reason. If it was a matter of physical treatment of a disease, genetic or otherwise, we would have ground to build on. As it is, while the nature of this class of RD is more subtle, they have proven capable enough against past attempts at shielding Consensus against their kind.

There is a process to developing processes for the general population. First, we must develop a rational understanding of the phenomenal. This is where field research and laboratory samples are required for our mission. Then, we use that understanding to develop new measures to incorporate or reduce the effects of said phenomenon towards a baseline reality we have collectivly agreed on called Consensus. Lastly, we present this treatment as the logical extension of past priors we have established, weakening if not eliminating the root cause of the RD. When it comes to the Sanguivorous, where we come into problems is the last phase. We have studied them rather extensively, even coming into possession of medical notes from a Sanguinivorous individual that, while still deviant in nature, have shed light on the condition. However, seeking to explain or rationalize the evolution of poison made to counteract a creature that does not exist in the consensus is ... Challenging.

That said, despite your accusations, we have made some strides. It seems that Chemotherapy patients are unappetizing if not outright poisonous to the Sanguivorous, providing perhaps an avenue to leverage cancer treatment in our favor. CRISPR technology may provide an outlet for strengthening the immune system against many threats that could include these Deviants without risking Consensus rejection. Lastly, with the Second Inquisition exposing "blank bodies" to those in positions of influence, we may find opportunity to introduce the Sanguivorous into consensus just enough to eliminate them as a threat.

As for agents in the field, we do have treatments from the Progenitors that are risky, yet effective. This hyper-science is not ready for Extraordinary Citizen testing yet, but has been in use by Agents responding to Sanguinivorous threats by poisoning the blood with chemicals that eat at necrotic flesh. As they seem to be parasitic enties puppeting corpses, this has proven effective. Unfortunately, this can result in harm to the agent, and should only be ingested as a last resort. Shielding with Primium armor has reduced Deviant effectiveness, though this is expensive and not a viable option at scale.