How to avoid the germs of a sick person at home?

Well, my younger brother hurled everywhere earlier and i don't know how to avoid getting ill. i have a fear of throwing up for a start which isn't very helpful. But then i also have 3 end-of-year tests this week and i can't afford to be off ill. Besides the obvious 'Wash hands' is there any way to avoid getting his germs?! I probably sound paranoid sorry. any advice would be great, thanks :) xx