cancer isn't a organic life-form.
As someone who's worked in a lab culturing cancer cells, I can tell you that it most certainly is. A tumor consists of your own body cells, growing out of control, and you are most definitely organic.
All those things - sealed atmosphere suits, decon sites, and vaccines - will give you an edge against some disease agents on an individual basis. None of them, however, is capable of protecting the entire human race. Nor are you likely to wear one your entire life. Biological agents are extremely insidious, almost impossible to contain.
All that aside, 'technological superiority' is arrogant and fallacious. We, humanity, are
entirely dependent on organic life - plants, insects, and the other elements of the ecosystem - for our continued survival. We have
never managed to create a successful artificial ecosystem.
As StratComm said, it's no coincidence that most of our current technological progress regards the manipulation of biological systems.