The prevalence of genital Chlamydia trachomatis in Australia 1997-2004: a systematic review.
OBJECTIVE
To determine by systematic review the prevalence of genital chlamydial infection in Australia between 1997 and 2004.


METHODS
Electronic literature databases, reference lists, and conference proceedings were searched and health agencies and jurisdictions were contacted for published and unpublished reports. Studies were eligible if they offered a diagnostic nucleic acid amplification test to consecutive individuals presenting during the study period. As a summary measure of the available data, mean prevalence rates, weighted by sample size and irrespective of participant age, were calculated for the population sub-groups.


RESULTS
40 studies of 50 populations and 40,587 individuals met the inclusion criteria, but only one of these was population-based. The use of non-systematic methodologies prevented an assessment of time trends and a statistical comparison of population sub-groups. The mean overall prevalence of genital chlamydial infection was 4.6% (95% CI 4.4-4.8%), reflecting over-sampling of high-risk groups. The mean community-based rates were 7.5% (95% CI 6.4-8.6%) and 8.7% (95% CI 7.9-9.7%) for Indigenous men and women, and 1.5% (95% CI 1.1-1.9%) and 1.4% (95% CI 0.9-2.0%) for non-Indigenous men and women. The overall mean estimates for other groups were 3.3% (95% CI 3.0-3.7%) for female attendees of sexual health and related clinics, 5.6% (95% CI 4.9-6.4%) for adolescents and young adults, 3.3% (95% CI 2.8-3.9%) for sex workers, and 1.6% (95% CI 1.2-2.0%) for urethral infection in men who have sex with men. Clinic-based estimates were generally, although not consistently, higher than community-based estimates. There is no serial population-based data for sexually active young men and women, but the available age-specific rates suggest under-ascertainment by the routine surveillance systems.


CONCLUSIONS
The prevalence of genital chlamydial infection in Indigenous Australians and young adults is unacceptably high and quality epidemiological studies are urgently required to supplement the routinely collected national notification data.
Vajdic
Claire M
CM
National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, Australia. cvajdic@nchecr.unsw.edu.au
Middleton
Melanie
M
Bowden
Francis J
FJ
Fairley
Christopher K
CK
Kaldor
John M
JM
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D002690:Chlamydia Infections / Q000175:diagnosis / Q000453:epidemiology*; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D005260:Female; D005831:Genital Diseases, Female / Q000175:diagnosis / Q000453:epidemiology*; D005832:Genital Diseases, Male / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data; D008875:Middle Aged; D015995:Prevalence; D011322:Primary Prevention / Q000592:standards; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution