Why have numbers tripled over the past decade, and what’s being done to rein them in?
The number of syphilis notifications recorded in the Australian National Notifiable Diseases Surveillance System rose from 1719 in 2013 to 6036 in 2022, according to the Kirby Institute’s latest annual report on STI trends.
Dr Sara Whitburn, chair of the RACGP sexual health medicine special interest group, told The Medical Republic multiple factors contributed to the dramatic increase in cases.
Some factors (such as decreased condom use and increased sexual mixing) also contributed to increases in other STIs such as chlamydia and gonorrhoea, while others (including screening and testing practices) were more syphilis specific.
“In the past, we would often test for syphilis based on perceived risk, [but] now we’re including it as part of our standard sexual health screen. We’re seeing a lot more asymptomatic [cases] – about 50% in our clinic – through routine screening,” Dr Whitburn explained.
While there hasn’t been a significant change in how syphilis presents, Dr Whitburn recommended keeping the possibility of syphilis front of mind when treating patients.
“In the past, genital ulcers were considered to be herpes until proven otherwise. But syphilis is the great mimicker, so if you see ulcers – even if they don’t fit the textbook of a syphilis chancre – we need to make sure we always test for herpes and syphilis,” said Dr Whitburn.
Associate Professor Jason Ong, a Melbourne-based sexual health physician, provided an extreme example of what can happen if syphilis is forgotten about.
“I heard a horror story recently about a woman had vulval lesions caused by syphilis, but no one thought about testing for it,” he told TMR.
“This woman went through 14 different specialists and ended up with a completely unnecessary vulvectomy when all she needed was to be tested for syphilis and treated for penicillin.”
Congenital syphilis case numbers have also increased, from seven in 2013 to 15 in 2022.
“We used to only test for syphilis once in pregnancy, but in response to rises in congenital syphilis, many jurisdictions around Australia are now testing multiple times during pregnancy,” said Professor Ong.
“Our current national guidelines suggest once at first antenatal visit, once at 28 to 32 weeks [and] one more time at delivery.”
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Syphilis numbers may continue to rise, but the upside is that more people can be treated rather than allowing it to spread through the community undetected.
However, several countries – including Australia – are experiencing shortages of benzathine penicillin, the recommended treatment for syphilis. The DoHAC and the TGA’s medicine shortage reports database report various doses of penicillin will have limited availability throughout 2024.
Clinicians and researchers are continually searching for alternative treatments.
“Doxycycline is a good second choice, [but] doesn’t have as much evidence as for penicillin and may not be as effective [as penicillin] especially when the full [two or four-week] course is not taken,” Professor Ong told TMR.
