With the ever forward-marching advance of genetic engineering, how long do you estimate, until you can buy vials of engineered diseases that have targeted symptoms?

50 years ago.

Genetic modifications are not necessarily diseases, and will probably always require medical supervision and application. I don’t know how long it would take but medical breakthroughs, as you state in your question, are ever-forward-marching and probably will be discussed soon in medical and National Geographic type journals. After its possible, it will probably take about fifteen years to be actually available.

250 years. They have a bigger problem right now combating antibiotic resistant infections and other superbugs.