Homeless young people: an important risk group for sexually transmitted infections

The prevalence of Chlamydia trachomatis infection in Australia: a systematic review and meta-analysis

BACKGROUND

Chlamydia trachomatis is a common sexually transmitted infection in Australia. This report aims to measure the burden of chlamydia infection by systematically reviewing reports on prevalence in Australian populations.

METHODS

Electronic databases and conference websites were searched from 1997-2011 using the terms 'Chlamydia trachomatis' OR 'chlamydia' AND 'prevalence' OR 'epidemiology' AND 'Australia'. Reference lists were checked and researchers contacted for additional literature. Studies were categorised by setting and participants, and meta-analysis conducted to determine pooled prevalence estimates for each category.

RESULTS

Seventy-six studies met the inclusion criteria for the review. There was a high level of heterogeneity between studies; however, there was a trend towards higher chlamydia prevalence in younger populations, Indigenous Australians, and those attending sexual health centres. In community or general practice settings, pooled prevalence for women <25 years in studies conducted post-2005 was 5.0% (95% CI: 3.1, 6.9; five studies), and for men <30 years over the entire review period was 3.9% (95% CI: 2.7, 5.1; six studies). For young Australians aged <25 years attending sexual health, family planning or youth clinics, estimated prevalence was 6.2% (95% CI: 5.1, 7.4; 10 studies) for women and 10.2% (95% CI: 9.5, 10.9; five studies) for men. Other key findings include pooled prevalence estimates of 22.1% (95% CI: 19.0, 25.3; three studies) for Indigenous women <25 years, 14.6% (95% CI: 11.5, 17.8; three studies) for Indigenous men <25 years, and 5.6% (95% CI: 4.8, 6.3; 11 studies) for rectal infection in men who have sex with men. Several studies failed to report basic demographic details such as sex and age, and were therefore excluded from the analysis.

CONCLUSIONS

Chlamydia trachomatis infections are a significant health burden in Australia; however, accurate estimation of chlamydia prevalence in Australian sub-populations is limited by heterogeneity within surveyed populations, and variations in sampling methodologies and data reporting. There is a need for more large, population-based studies and prospective cohort studies to compliment mandatory notification data.

Diagnosis of sexually transmitted infections (STI) using self-collected non-invasive specimens

Paramount in control of transmission of sexually transmitted infections (STIs) is their prompt recognition and appropriate treatment. In countries where definitive diagnoses are difficult, a 'syndromic approach' to management of STIs is recommended and practiced, yet many STIs have common symptoms or are asymptomatic and therefore go undetected and untreated. This is of particular concern with the recognition that HIV transmission is increased with co-existent STIs: the attributable risk for each STI varying with the prevalence within a particular population. Hence, HIV public health prevention approaches must include STI preventative strategies to be effective. Even then, microbiological screening is incorporated into STI control strategies; lack of access to appropriate services (especially in rural and remote areas), reluctance of at-risk populations to attend for treatment, fear of invasive genital examinations, and lower sensitivities of conventional diagnostic assays reduces the effectiveness of such programmes. Therefore, accurate, cost-effective, reliable diagnostic assays (preferably those which can be used in the field) are needed to impact on the incidence of the various STIs, as well as HIV. With the advent of molecular technologies, including target and signal amplification methods, diagnoses of STIs have been revolutionised and allow the use of non or minimally invasive sampling techniques, some of which are self-collected by the patient, e.g. first-void urine, cervico-vaginal lavage, low vaginal swabs, and tampons. Most studies evaluating such self-sampling with molecular diagnostic techniques have demonstrated an equivalent or superior detection of STIs as compared to conventional sampling and detection methods. These sampling methods can also be used to determine prevalence of STIs in various populations, but particularly those with difficult access to medical care. In this article, the utility of self-sampling collection devices for detection of various STIs, particularly in women, is reviewed as one step towards formulating appropriate strategies in control of STIs, and which are especially suited for remote areas.

Screening injecting drug users for sexually transmitted infections and blood borne viruses using street outreach and self collected sampling

BACKGROUND

Injecting drug users (IDUs) are a marginalised population, who infrequently access health services for screening for sexually transmitted infections (STIs) and blood borne viruses (BBVs), and are at high risk of these infections.

OBJECTIVES

To use street outreach and self collection of samples for STI screening, to establish the prevalence of BBVs and STIs, and to identify risk behaviours among a group of culturally diverse street based IDUs.

METHODS

This was a cross sectional study of 314 IDUs in the central business district of Melbourne, Australia, conducted over 3 years (1999-2002). We used street outreach as the recruitment strategy with staff "on foot" in injecting and dealing locations, as well as self collected genital sampling to increase acceptance of screening for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis by polymerase chain reaction (PCR). Individuals were screened for hepatitis A, B, and C, syphilis and HIV, and given the option of a self collected or clinician collected blood sample to increase acceptance of screening for BBVs.

RESULTS

Street outreach was highly effective and self directed STI sampling was more acceptable than practitioner directed sampling (76% versus 9% acceptance, p<0.001). There was a high prevalence of hepatitis C (74%, 95% CI 69 to 79), STIs (8% (5 to 13)), and chlamydia (6% (3 to 10)), and past exposure to hepatitis A and B was common. High rates of recent sharing of injecting equipment, unprotected sex and casual sexual partners, together with low levels of awareness of current hepatitis C infection were identified.

CONCLUSION

Street outreach and self collected genital samples facilitate screening for STIs and BBVs in IDUs and revealed a high prevalence of infections and risk behaviours.

The prevalence of genital Chlamydia trachomatis in Australia 1997 - 2004: a systematic review

Objectives: 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 40587 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.