I am studying in college. I stay in a 3 sharing room. One of my roommate suffered from chickenpox 2 weeks before. He went to home back then, got cured and came back from home last week. I was afraid as I share the room with him. After about 5 days or so, another roommate (who stays alone in a separate room) of mine got chickenpox. The other one went to home this week. Now, I am afraid that after he comes back I might get the disease. Lastly, I want to mention that I already had suffered from chickenpox in my childhood. Is there any precautions I can take ? Is there any anti-biotic/anti-chickenpox that I can take ? Can chickenpox happen twice in a lifetime ? What are the things that spread it ?