Preventing STI infection is important for all sexually active people.
For people living with HIV, the importance is much greater, as HIV may have already damaged the immune system. This can make the impact of some STIs more severe, and more difficult to treat.
Having another infection can increase the risk of HIV transmission. STIs such as gonorrhoea or genital warts can increase the viral load (the amount of virus) of a person living with HIV, making it more likely for HIV to be passed on during unprotected sex.
For a person who is HIV negative, having another infection can make it easier to contract HIV. For example, STIs like syphilis, genital warts or herpes can cause sores, blisters or broken skin which can create openings where HIV can get in (or get out) of the body.