SEXUALLY transmitted infections are on the march. In Australia, where the , rates of syphilis, gonorrhoea and chlamydia are the highest they have been since national recording began in the 1990s.
The story is similar in England and the US, where rates of these STIs have been climbing over the last decade (see graphs).
This uptick is alarming because these diseases were thought to be on their way out. In the 1940s, penicillin was tipped to eradicate syphilis, as swathes of soldiers infected during the second world war were cured. Gonorrhoea rates also plummeted in the 1980s, as fear of HIV spurred safer sex practices.
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One factor in the resurgence is simply that we are doing more testing, particularly for chlamydia, says at the University of New South Wales in Australia. People with the disease don鈥檛 normally show symptoms, but since the first accurate chlamydia test became widely available in the early 2000s, testing has increased, meaning more and more silent infections have been picked up.
But that isn鈥檛 the whole story, says at University College London. Another driver may be the popularity of dating apps like Tinder and Grindr, which make it easier to hook up with more people, he says. That generally isn鈥檛 a problem if people use condoms, but online daters appear to be less likely to practise safe sex.
A large study by Field and his colleagues found that men in the UK who used online dating services were more likely to have had sex with five or more people in the previous year, compared with those who didn鈥檛. They were also 1.5 times more likely to have had sex without a condom with two or more partners in that time. Similarly, a recent study of 500 male and female US college students found that those who used dating apps were as likely to have had unprotected sex in the previous three months.
鈥淏ritish men who use online dating services are more likely to have sex without using a condom鈥�
It is hard to tell whether dating apps are simply an indicator of risky sexual behaviour, or actively driving it, says Field. 鈥淚t might be the case that people who already had lots of casual unprotected sex are more likely to use dating apps.鈥�
Regardless, these services might make it easier for high-risk people to have sex with more partners and spread STIs, he says. They may also link up different groups of people who might otherwise not have had sex, allowing greater spread of STIs.
But let鈥檚 not be too quick to blame technology alone. Condoms, one of the best defences against STIs, have fallen out of favour as people become less scared of HIV. Antiretroviral drugs have increased the life expectancy of people with HIV to and drastically reduced transmission rates. Moreover, since 2012, pre-exposure prophylaxis (PrEP) medicines have been available to some high-risk groups to protect them against contracting the virus. Taken together, this has led some HIV-positive men to ditch condoms.
A , Australia, of almost 3000 men who have sex with men found the proportion who always used a condom during casual sex dropped from 48 per cent in 2013 to 30 per cent in 2017. At the same time, PrEP use increased from 1 to 16 per cent.
Syphilis, gonorrhoea and chlamydia don鈥檛 have the same fear-factor as HIV because they are bacterial infections that can be treated with antibiotics. However, many people don鈥檛 get symptoms, so they don鈥檛 know they are infected. Down the track, untreated infections can lead to pelvic inflammatory disease, infertility, ectopic pregnancy, arthritis and other health problems. It is estimated that chlamydia increases the risk of infertility by about , for instance.
More worryingly, bacterial STIs are starting to develop resistance to antibiotics. Gonorrhoea has developed the strongest resistance, and reports have already emerged of strains that don鈥檛 respond to .
Time for sex ed
鈥淚f we run out of effective antibiotics and gonorrhoea continues to increase, we鈥檒l have a much bigger problem on our hands,鈥� says Guy.
The first step to reversing the climb in STI cases is education, says Field. This starts in school, but high-risk adults should also be targeted, he says: 鈥淔or example, ads reminding people to use condoms and get tested could be built into dating apps.鈥�
There is clearly room for improvement here. A , Australia, last month found that 60 per cent of 15- to 29-year-olds incorrectly believed the contraceptive pill offered protection from STIs, while 52 per cent believed the withdrawal method did the same.
Personalised feedback could also work, says at the University of North Texas. Her research group recently used this approach to reduce risky sexual behaviours in young adults in the US.
They surveyed 1000 people aged 18 to 25 to find out how often they drank heavily, had casual sex and used condoms. Those at the riskier end of the spectrum were emailed personalised feedback showing how they compared with their peers. One month later, they reported adopting safer practices. 鈥淧eople don鈥檛 like standing out from the pack,鈥� says Lewis.
Making STI testing easier and more accessible is also important, says Field. People often shy away from getting tested because they don鈥檛 want to have an awkward chat with their doctor.
To get around this, researchers at the London School of Hygiene and Tropical Medicine recently sent text messages to 1000 people aged 16 to 30 with a link to an online provider of . Those who signed up were posted a kit with instructions on how to collect their own samples. After mailing them back, they received their results within seven days.
The who received this message completed the DIY test. In comparison, when 1000 other people were sent a text message with details of their local sexual health clinics, only 27 per cent went for a test.
For people who test positive, public health experts have also devised ways to take the cringe factor out of notifying former partners. Free online services like , , and It now allow people to send anonymous emails or text messages to former sexual partners to recommend they get tested.
The ultimate aim, of course, is the development of vaccines that prevent people from catching STIs in the first place. But these are still a fair way off.
One of the most promising candidates is a chlamydia vaccine that is being tested in an initial at Imperial College London after proving highly effective in mice. So far, the trial has found the vaccine to be safe in humans, but whether it prevents infection is still being evaluated.
鈥淚t is estimated that chlamydia increases the risk of infertility by about 30 per cent鈥�
No gonorrhoea-specific vaccines have made it to clinical trials yet, but a study published last year found that the meningococcal B vaccine offered surprising cross-protection against gonorrhoea. In 15,000 young people in New Zealand, the vaccine reduced gonorrhoea infections by . Syphilis vaccines are still in the preclinical testing stage, but several look .
In the meantime, the focus remains on improving education and testing. The internet may be both a friend and foe 鈥� facilitating STI spread via dating apps, but also providing a platform for targeted awareness campaigns and anonymous testing and partner notification.
Until vaccines become available, the most important public health message is still the same as it was during the second world war, when to protect them against STIs. Their advice? 鈥淐rossing your fingers won鈥檛 prevent venereal disease, but a prophylaxis will鈥�.
This article appeared in print under the headline 鈥淜eep it clean鈥�
