Skull & Bones couldn't do anything of that sort even if they wanted to. What Skull & Bones is, is a recruitment agency where "promising" students ─ read: students with a good chance of ending up in positions of power some day due to their skills, the power of their families, or both ─ are being compromised and then recorded on camera without their knowledge, so that they can become manipulable puppets in the hands of The Powers That Be™ once they graduate.
It's a vile and abject concept, but that's all they do. They certainly don't have the power, knowledge or resources to engineer a killer virus. They're simply a little student mafia club where extortion is the game. Every member of the club has skeletons in his closet that they don't want the world to find out about. The club itself makes sure of that, because that is after all its very reason of being.