Dr. Cottle says that the Cylons have an antibody in their blood that destroys "the RNA of the vaccine", which is why they would need multiple shots to stay alive. This makes no sense scientifically, as the vaccine's RNA is the RNA of the virus. If the Cylons have an antibody against it, that not only means that they have come in contact with the virus before, but also that they are actually *immune* to it, since they have a defense mechanism that kills it.
Dr. Cottle proposes he make a vaccine to "reverse the effect of the virus on the Cylons". However, a vaccine is meant to *prevent* a disease and not cure it or make its symptoms more tolerable, once they have manifested.