Sexually transmissible infections

Gonorrhoea cells


The HIV, Viral Hepatitis and Sexually Transmissible Infections in Australia Annual Surveillance Report analyses data on sexually transmissible infections (STIs), including chlamydia, gonorrhoea, syphilis, human papillomavirus (HPV) and donovanosis. Simple treatments are available for most of these sexually transmissible infections. However, if left untreated, chlamydia and gonorrhoea can cause pelvic inflammatory disease in females and infertility in both males and females, while untreated syphilis can cause serious long-term conditions including heart failure, dementia, blindness and brain damage.

In 2017, there were an estimated 255,228 new chlamydia infections in people aged 15–29 years. Both testing and diagnoses of chlamydia have increased in the past five years. However, almost three quarters of infections in young people remain undiagnosed and untreated. 

There were 28,364 diagnoses of gonorrhoea and 4,398 diagnoses of infectious syphilis in 2017, with the vast majority of diagnoses for both infections in males. Gonorrhoea and infectious syphilis in Australia are diagnosed primarily in men who have sex with men in urban settings, and in young heterosexual Aboriginal and Torres Strait Islander people in remote areas, although the number of new diagnoses of gonorrhoea among women in urban settings has also been increasing steadily. 

Among Aboriginal and Torres Strait Islander people, chlamydia and gonorrhoea rates were three and seven times higher than in the non-Indigenous population and the gaps were greater in regional and remote areas.

There has been a marked reduction in diagnoses of genital warts in younger age groups, due to the introduction of a human papillomavirus vaccination program in 2007.


You can explore the STIs data from Australia in the interactive graphs below.

Scroll down to read the interpretation of the data and to download the full version of the report.

What's new in 2017?

What does this mean?

Both testing and diagnoses of chlamydia have increased in the past five years. However, the vast majority of infections in young people remain undiagnosed and untreated, highlighting the need for testing to be routinely offered to sexually active adolescents and young adults.

Gonorrhoea and infectious syphilis have been diagnosed more frequently in the past five years in gay and bisexual men, with the highest rates in younger men and in men living with HIV. Explanations for these increases in gay and bisexual men include more comprehensive screening, a change to more sensitive gonorrhoea testing technology, and an increasing trend in condomless anal sex in the context of the greater availability and awareness of highly effective HIV prevention strategies. Efforts to improve health promotion, testing and treatment in gay and bisexual men need to be strengthened.

The increase in the ratio of gonorrhoea diagnoses to Medicare‑rebated tests among both men and women between 2013 and 2017 suggests increasing transmission through heterosexual sex, highlighting the need for health promotion, enhanced testing and partner notification in heterosexual men and women. 

The increases in infectious syphilis in young Aboriginal people in remote communities, along with cases of congenital syphilis, emphasise the need to enhance culturally appropriate health promotion, testing and treatment strategies in this population.