Carol El-Hayek (left) with Burnet Institute's Infectious Diseases Surveillance Group.
By Kate Hagan, The Age
Girls aged 12 to 15 years are testing positive for chlamydia at a higher rate than older women, new research shows, prompting concerns they are not practising safe sex.
The Burnet Institute study analysed chlamydia testing for people aged under 25 years from 15 laboratories across Australia between 2008 and 2010.
Researchers led by Burnet epidemiologist Carol El-Hayek broke down the results by gender and across three age groups.
They found girls aged 12-15 years had the highest percentage of positive tests (13 per cent), compared with females aged 16-19 years (12 per cent) and 20-24 years (8 per cent).
Among males, the highest percentage of positive tests was in those aged 16-19 years (15 per cent), followed by 20 to 24-year-olds (13 per cent) and 12 to 15-year-olds (9 per cent).
Ms El-Hayek said her study included about a dozen 12-year-old girls who had tested positive for chlamydia, but 14 and 15-year-olds were more commonly diagnosed in that age group.
She said chlamydia disproportionately affected sexually active young people, with the number of diagnoses tending to decline as people reached their 30s. More women than men are affected, particularly in younger age groups.
Chlamydia is spread through unprotected vaginal, anal or oral sex and is often asymptomatic, but can cause long-term complications if left untreated, including infertility.
Ms El-Hayek said her study showed fewer tests were performed on 12 to 15-year-old girls than older females, possibly because they were only tested after presenting with symptoms or if identified as being at risk of unprotected sex.
She said older women were screened more routinely and therefore likely to return more negative tests.
‘'Clearly Australian adolescents as young as 12 are vulnerable to sexually transmitted infections, but the younger they are, the less likely they are to be tested,’‘ she said.
The study, to be presented at the Australasian sexual health conference in Darwin on Thursday, comes as a new report by the Kirby Institute shows chlamydia remained the most frequently notified infection in Australia last year, with 82,707 cases diagnosed - up from 80,922 in 2011.
Kirby Institute program director David Wilson said rates of chlamydia had roughly tripled over the past decade, mainly due to increased testing, with young people and indigenous Australians most affected.
CLICK HERE to watch a story on ABC’s Lateline, featuring this research.