- A common bacterial STI, spread by unprotected vaginal or anal sex
- Most prevalent in people aged under 25
- Called a 'silent infection' because most people do not realise they have it
- Can cause pelvic inflammatory disease, which can lead to chronic pain and infertility
- Can be easily diagnosed with a urine or swab test and treated with antibiotics
Girls aged 12 to 15 have the highest rate of chlamydia among females, a new study will reveal.
More than one in eight girls in this age group tested positive for the sexually transmissible infection (STI) — which is a higher rate than seen in older teens or young women.
The shock finding — to be presented today at the Australasian Sexual Health Conference in Darwin — is causing concern because chlamydia can cause infertility and reproductive problems later in life.
It also comes at a time when young people appear to be less conscious of STIs: another study to be presented at the conference reveals only one in seven at risk of an infection is aware of it.
Public health statistics on chlamydia are usually published from the age of 15 upwards. Diagnosed in 82,707 Australians last year, it is the country's most commonly reported STI.
But experts warn this is "just the tip of the iceberg" as it may show no symptoms and most people carrying the infection are undiagnosed.
The real figure is estimated to be five times higher — or closer to half a million people infected.
According to the new study, conducted by the Burnet Institute and based on data from five states over three years, 13 per cent of girls aged 12 to 15 tested positive for chlamydia. The rate is 12 per cent for 16 to 19-year-olds and eight per cent for 20 to 24-year-old women.
Lead researcher Carol El-Hayek said the higher rate in young girls could be partly explained by the fact they were more likely to be tested after seeking medical attention for "identified sexual risk or symptoms", whereas older girls and women were more likely to undergo routine tests.
"The sexual behaviour of younger adolescents potentially increases their risk of infection but little is known about their sexual risk practices," she said.
"We need a better understanding of the sexual risk practices of young people in order to minimise their risk and ensure they have access to testing and treatment."
The rate of chlamydia in boys is highest in 16 to 19-year-olds at 15 per cent, compared to nine per cent of 12 to 15-year-olds and 13 per cent in 20 to 24-year-old men.
WHAT IS CHLAMYDIA?