What the bat lady was working on was prior to, years prior to, the outbreak, and it contained information about the splicing of certain elements of the aids virus, among a host of other stuff, using bats in the research. Now they can use the lethality or non-lethality of any number of viruses to build a virus. That took decades to accomplish. If they want a virus to be highly transmissible, they'll use part of a virus from the past that gave it it's high transmissibility, likewise, building it's mutations, they can lessen the transmissibility as "more people become immune" or "it weakens in nature" or any host of reason that follow a course of action related to viruses in the natural evolution of a virus. Why some people get it and others don't is a question of many different attributes, their immune systems, precautions they take, what they eat that boost their immune response, or they simple caught a less lethal/transmissible mutation. To try and say what you are saying, is like calling every person in the medical field who has the ability to research, view, viruses a liar, it's just to wide a conspiracy to believe. Way to many people in the know trying to keep a secret? I don't think so.