3D graphic of syphilis

Sexually transmissible infections are on the rise in Australia, with syphilis rates tripling over the decade

An annual report on STIs has revealed concerning trends.

Media release | Published on 18 Dec 2023

Over the past 10 years, Australian diagnoses of gonorrhoea have doubled, while diagnoses of syphilis have tripled, according to a new report released today by the Kirby Institute at UNSW Sydney.

Chlamydia is increasing too (up 12 per cent since 2013), and low rates of testing brought on by the COVID-19 pandemic have researchers concerned that the upward trends are likely to continue. 

“Any rise in STIs is bad news, but rising STIs against a backdrop of decreased testing, and the persistent upward trend over the past decade, is particularly concerning,” says epidemiologist Dr Skye McGregor, who leads the report at the Kirby Institute. 

There has been a decline in the number of Medicare-rebated tests for chlamydia and gonorrhoea among both men and women between 2019 and 2022, which is likely due to the ongoing impacts of the COVID-19 pandemic.

“Chlamydia, gonorrhoea, and syphilis are all easily treatable with antibiotics. The key message we want Australians to take away from these data is that for any sexually active person, condoms remain highly effective at preventing STIs, and regular STI testing is crucial,” says Dr McGregor.

“A key part of this is combating stigma around sexual health and notifying sexual partners when someone has tested positive for an STI. Early testing, diagnosis, and treatment of STIs prevents serious long-term outcomes.”

In 2022 there were 93,777 diagnoses of chlamydia, 32,877 diagnoses of gonorrhoea and 6,036 diagnoses of infectious syphilis.

Syphilis rates are of concern

The number of syphilis cases has more than tripled in the past 10 years, and even though most cases remain in men, there has been a six-fold increase in the number of females diagnosed with syphilis over the same period.

“The rise in syphilis among women is very concerning because while syphilis is entirely treatable, if untreated in pregnancy, infection can lead to miscarriage or stillbirth, or congenital syphilis, which is when the infection is transmitted to unborn children. Congenital syphilis is an extremely serious condition for infants that can result in significant lifelong health impacts, and in the most severe cases can be fatal,” says Dr McGregor.

According to the report, there were 15 congenital syphilis cases in 2022, eight of which were among Aboriginal and Torres Strait Islander peoples. There have been 69 cases of congenital syphilis in the past seven years, 18 of which resulted in the death of the infant.

“Congenital syphilis diagnoses are 14 times as high among Aboriginal and Torres Strait Islander infants compared with non-Indigenous infants. All pregnant people should be tested for STIs as part of pre- and antenatal health screening, but antenatal care is not always accessible. It is vital that comprehensive services are in place to ensure appropriate care is accessible for all pregnant people,” says Dr McGregor.

The number of congenital syphilis diagnoses was low across all populations from 2013-2019, and the rise in cases since the pandemic has researchers, community groups, and health departments very concerned.

“With timely screening, syphilis can be cured, so even one case of congenital syphilis is completely avoidable and unacceptable. We are working with our partners to urgently understand and address this breakdown in pre-natal screening,” Dr McGregor says.

Most chlamydia undiagnosed

According to the report, most chlamydia cases in Australia are undiagnosed and untreated, reinforcing the need for increased testing. Untreated, chlamydia can cause serious long-term health consequences like pelvic inflammatory disease in women and infertility in men and women.

“If you are sexually active, the best thing to do is to have a chat with your GP, nurse, or health worker about the risk of STIs, and they’ll recommend anything from three to 12 monthly testing, depending on risk. Chlamydia and gonorrhoea are tested for using a simple urine test or a self-collected vaginal swab. It’s also recommended to get a blood test for syphilis and HIV at the same time,” says Dr McGregor.

Chlamydia was the most frequently notified STI in Australia in 2022, with more than two in three diagnoses occurring in young people aged 15 to 29 years.

“We estimate that one in 27 young females in Australia had chlamydia at some point in 2022, with less than half being diagnosed. That equates to over 91,000 young women,” says Dr McGregor. 

Higher burden for Aboriginal and Torres Strait Islander peoples

In 2022, Aboriginal and Torres Strait Islander peoples continued to experience significantly higher rates of STIs that non-Indigenous Australians.

“Aboriginal and Torres Strait Islander peoples are diagnosed with chlamydia two times more frequently than non-Indigenous people. For gonorrhoea and syphilis, the rate is more than five times as high. These disparities are even more significant in regional and remote communities,” says Robert Monaghan, a Bundjalung-Gumbaynggir man and Manager of Aboriginal and Torres Strait Islander Health Research at the Kirby Institute.

“This highlights an urgent need for culturally appropriate health promotion, testing, and treatment strategies. It is crucial that these are co-designed with Aboriginal and Torres Strait Islander peoples.

“While these statistics are incredibly concerning, we know that well targeted and appropriately funded health interventions work in our communities. For instance, HPV vaccination has been hugely successful, with no diagnoses of genital warts in 2022 among young Aboriginal men aged under 21 years, attending clinics included in the Australian Collaboration for Coordinated Enhanced Sentinel Surveillance network.”

Gonorrhoea and syphilis most common in men

Gonorrhoea also increased in 2022, and diagnoses in major cities were almost three times as high in in 2022 than they were 10 years ago. Most diagnoses (71 per cent) were among males.

“When we look closely at the data, most gonorrhoea diagnoses are among gay and bisexual men. Alongside encouraging regular testing, this prompts us to investigate emerging prevention approaches, such as vaccination,” Dr McGregor says.

Syphilis was also most prevalent in men, at 82 per cent of diagnoses nationally, with variation in this proportion by state and territory. The report estimates that both infections have been increasing in gay and bisexual men in recent years.

“We infer an increase in STIs among gay and bisexual men by analysing the diagnoses by sex and seeing disproportionate numbers among men compared to women,” says Professor Andrew Grulich, head of the HIV Epidemiology and Prevention program at the Kirby Institute.

“It is likely that these increases can be explained by more comprehensive screening and greater availability and awareness of highly effective HIV prevention strategies and in turn a decrease in the use of condoms and greater sexual mixing.”

“But we know how effective health promotion can be in this community, as we have seen with the huge reductions in HIV. We need to carry over these learnings to STIs, to drive down infections in this group.”

Eliminating some STIs

Australia has made significant progress in the elimination of genital warts due to the impact of the HPV vaccination program: the proportion of non‑Indigenous females aged under 21 years attending sexual health clinics diagnosed with genital warts, which are caused by HPV, has decreased from 10.6 per cent in 2007 to 0.2 per cent in 2022. 

“Australia is a leader in the rollout of the HPV vaccine, and it is very encouraging to see that genital warts diagnoses are so low among this population,” says Professor Basil Donovan AO, a sexual health physician and head of the Kirby Institute’s Sexual Health Program.

Similarly, Australia has likely eliminated donovanosis, which was once a regularly diagnosed STI in remote Aboriginal communities. The most recent case was notified in 2014, with zero cases diagnosed since then.

“It is important that we look to these examples as an encouraging sign of what can be achieved when concerted efforts are made across sectors. It is important that we target the necessary resources to other STIs, to improve the health and wellbeing of all Australians,” says Prof Donovan.

Download the full report.
Explore the data on this interactive data site.