Please cite a peer reviewed, reputable medical journal study which confirms this is a bioweapon or STFU. Please do not cite some bullchit you read off of Zerohedge, 4Chan or Reddit.

Your answer? Overt v. covert. Panic. Financial market instability. Difficulty in tracing sources and pinning responsibility. Easier to hide, transit & deploy. Elimination of an enemy without having to fire a shot. Arms embargos. It's cheap and relatively easy compared to dev'ing ICBM's. Programs can be easily hidden from prying eyes. There are more medical experts than weapons experts (access to education, universities).