What's the worst STI?

If you're asking which STI has the most serious consequences if left untreated, it's HIV.

Untreated HIV attacks the immune system and eventually leads to AIDS, which can be fatal. But with modern medication, people with HIV can live long, healthy lives and reach the point where they can't pass the virus on. Treatment has changed the picture completely.

Beyond HIV, untreated syphilis can cause serious long-term damage to the brain, heart, and other organs if it progresses through its later stages. And certain strains of HPV can lead to cancer (most commonly cervical cancer), though the HPV vaccine, which is offered to all young people in UK schools, protects against the most dangerous strains.

Most other STIs, like chlamydia, gonorrhoea, and trichomoniasis, are treatable and won't cause serious harm if caught early. The problems tend to come when they're left untreated for a long time, which can lead to things like pelvic inflammatory disease or fertility issues.

Getting tested regularly and treated quickly makes most STIs straightforward to deal with.

The most serious STI if left untreated is HIV. Without treatment it attacks the immune system and can lead to AIDS, which can be life threatening. But with modern medicine, people with HIV take daily tablets and live long, healthy lives.

Untreated syphilis can also cause serious damage to the brain and heart over time. And some types of HPV can lead to cancer, though the HPV vaccine protects against the most dangerous types.

Most other STIs like chlamydia and gonorrhoea are easy to treat if caught early. Problems usually only happen when they are left untreated for a long time.

Getting tested regularly and treated quickly makes most STIs straightforward to deal with.