

Human: Do you know what can prevent the risk of getting aids?

Assistant: 
The greatest risk of contracting HIV or hepatitis B is through sexual transmission.  While there are still high-risk behavior factors associated with both viruses (unprotected sex, having many sexual partners, sharing needles, etc.), several effective prevention measures are available.  
It’s difficult to say.  To be truly safe, people should always use protection when they have sex.  This includes abstaining, using a condom, and having unprotected sex only with an HIV-negative partner.