Finally, some good news about STIs: there could soon be a chlamydia vaccine.

Image: Poor Miranda.

Rarely do you see the words “STI” and “good news” in the same sentence, but here we are: finally, we have some good news concerning STIs.

More specifically, it concerns the most common sexually transmitted infection in Australia — the one that affects both women and men, with more than half of all cases occurring in the 15-24 year age group.

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Yep, we are talking about chlamydia.

Thanks to Mean Girls, you know how not to spell it.


At the moment, the only way to protect yourself from this common yet nasty bacterial infection is through safe sex with barrier contraception; scientists have been unable to develop a vaccination to quell its spread.

However, thanks to a new study, things are beginning to look promising on the chlamydia prevention front.

As The Verge reports, a research team has recreated chlamydia inoculation trials that took place in the 1960s. This (highly unethical) test failed dramatically because the vaccines, administered to otherwise healthy men, women and children living in countries like India and Ethiopia, didn't actually work.

In some cases, subjects actually became more susceptible to contracting the disease. (Post continues after gallery.)

This time around, scientists injected mice with live or dead chlamydia bacteria, chased with a second injection of live bacteria. The mice injected with dead bacteria first were more likely to be infected with chlamydia.

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Essentially, this happened because the dead bacteria suppressed the mice's immune function — which suggests the immune system actually detected the bacteria. Using this finding, the researchers attempted to teach the animals' immune systems, particularly a certain type of white blood cells, that the bacteria should be killed off. (Post continues after gallery.)


You can read a more in-depth rundown of the process here, but in short: the scientists formulated a nasal spray using a combination of dead chlamydia bacteria and nano particle adjuvents (adjuvents are used in most vaccinations to boost the immune system's response).

The nasal delivery allowed this vaccine to target the 'mucosa' that covers the uterus, which is where chlamydia takes up residence in women.

This nasal formula kept the mice healthy and protected from chlamydia for an impressive six months. Hopefully a human-friendly form of the vaccine will be available in years to come, because chlamydia is one hell of a nasty disease.

For now, stick with condoms.


Chlamydia doesn't always present with immediate symptoms, which isn't great because if left untreated the infection can have some damaging long-term effects — particularly for women.

It can lead to pelvic inflammatory disease, a condition that can damage or block the fallopian tubes, cause chronic lower back pain, and even impact on fertility and ectopic pregnancy.

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Until this much-needed vaccine becomes available, keep using condoms and other barrier methods, and if you notice unusual symptoms (painful sex or unusual discharge, for instance) make an appointment with your GP.

Have you ever had chlamydia? Did you experience any symptoms?