When Rachel is chasing the runner, after he gets hit by the car she has no blood on her, because she was too far away from him. However, as she's running up to him, she goes from being clean in one shot to inexplicably having droplets of blood on her face in the next.
Dr. Hood states that "no biological contagion could survive 200 years without subzero suspension." However, bacterial spores, mold, and fungi can all survive hundreds and even thousands of years.