Significant rise in most STIs over the last 10 years
16 Sep 2025
Newly released data shows that diagnoses of syphilis and gonorrhoea in Australia have more than doubled over the past decade, chlamydia cases remain high, and HIV diagnoses have fallen.
The Kirby Institute at UNSW Sydney presented the findings at the Australasian HIV & AIDS Conference in Adelaide this week. In 2024, there were 5,866 syphilis diagnoses, representing a doubling over the last 10 years. Congenital syphilis cases have also risen, resulting in 34 infant deaths over the same period. The rising cases contributed to syphilis being declared a Communicable Disease Incident of National Significance by Chief Medical Officer Professor Michael Kidd.
Gonorrhoea cases have also doubled over the decade, with 44,210 diagnoses recorded in 2024. Chlamydia remains the most common STI, with 101,742 cases last year, around half of which were among people aged 20 to 29.
HIV, by contrast, has declined. There were 757 new diagnoses in 2024, a 27% decrease over 10 years. Chair of RACGP Specific Interests Sexual Health, Dr Sara Whitburn, said the rising STI numbers are likely due to increased testing, but they also show that STIs are spreading across different populations. She added that the decline in HIV is a positive outcome of widespread PrEP use, access to antiretroviral treatment, and the U=U strategy.
Dr Skye McGregor, epidemiologist at the Kirby Institute and lead author of the report, noted that while 80% of syphilis cases are among men, notifications among women have increased by 300% over the past decade, highlighting the risk of congenital syphilis.
The data also shows that Aboriginal and Torres Strait Islander people continue to experience higher STI rates. More than half of the 34 congenital syphilis deaths were among Aboriginal and Torres Strait Islander infants. Dr Whitburn emphasised the important role of general practitioners in educating patients, offering asymptomatic testing, and providing care during pregnancy.
HIV diagnoses among Australian-born people have almost halved, but rates among people born overseas have not decreased. Scott Harlum, President of the National Association of People with HIV Australia, stressed the need for ongoing investment and action to work towards virtual elimination of domestic HIV transmissions by 2030.
Source: Kirby Institute, UNSW Sydney; newsGP
