The body's resistance to illness vanished almost overnight. Caught by walking through someone's sneeze and it was possible to get it from toilet seats. If skydark hadn't ended civilization, it could have chilled more people than the Black Death.
There were many ways you could pick it up. Any sort of contact, no matter how casual, spread the virus, which was always a hundred percent terminal. It was easily detected, and there was talk about concentration camps and portable crematoria and even IE." (Ice and Fire)