See my previous post. The family at home had to deal with a lot less hazardous waste than the nurses. The difference if you read the study I linked, is blood. Blood has lots of viruses, saliva only has a few at the beginning due to enzymes breaking down the viruses. Once a victim like Patrick Sawyer was spewing blood on a flight hours before death we saw him infect the woman next to him and the flight attendants who cleaned up the blood. (no other passengers were infected). Nothing could have neutralized the virus at that point, not enzymes in the saliva or stomach acid...
Anyone throwing up violently has blood in their emesis, whether visible or not. I am highly suspicious that the family was able to avoid infection given the close quarters and significant exposure. And there are plenty of viruses in units other than blood as well....