Analysis of diagnostic data for sexually transmissible infections in South Australian Aboriginal Community Controlled Health Services (2008-16)

Australian Aboriginal communities experience a high burden of sexually transmissible infections (STIs). Since 2009, a comprehensive sexual health program has been implemented at nine Aboriginal Community Controlled Health Services in South Australia. This study assessed trends in STI testing and positivity using deidentified diagnostic data from this period (2008-16).

METHODS

Testing data for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG) and Trichomonas vaginalis (TV) from one urban, three regional and five remote Aboriginal health services were analysed using logistic regression.

RESULTS

From 2008 to 2016, testing increased for CT (twofold), NG (threefold) and TV (sixfold). On average, 30% of testing occurred during an annual 6-week screen. Fewer males were tested (range 27-38% annually). Mean annual STI testing coverage was 28% for 16- to 30-year-old clients attending regional or remote services (2013-16). Positivity at first testing episode for all three infections declined during the study period. From 2013 to 2016, when testing was stable and changes in positivity were more likely to indicate changes in prevalence, there were significant reductions in CT positivity (adjusted odds ratio (aOR) 0.4; 95% confidence interval (CI) 0.2-0.5) and TV positivity (aOR 0.6, 95% CI 0.4-0.9), although declines were statistically significant for females only. There was no significant decrease in NG positivity (aOR 0.9; 95% CI 0.5-1.5).

CONCLUSIONS

Since the sexual health program began, STI testing increased and STI positivity declined, but significant reductions observed in CT and TV positivity were confined to females. These findings suggest evidence of benefit from sustained, comprehensive sexual health programs in Aboriginal communities with a high STI prevalence, but highlight the need to increase STI testing among men in these communities.

Long-term trends of Chlamydia trachomatis in a clinic population at the Royal Women's Hospital, Melbourne

BACKGROUND

Chlamydia trachomatis (C. trachomatis) prevalence has been reported to be increasing. Whether this is a true increase over time or confounded by increases in testing and/or use of more sensitive assays is to be determined.

MATERIALS AND METHODS

One laboratory service has been detecting C. trachomatis for the past 30 years within the Royal Women's Hospital Melbourne. We conducted a retrospective audit of records over the period 1986-2016 from a clinic population routinely offered chlamydia screening. These were women presenting for family planning advice (termination of pregnancy, intrauterine device insertion or considered at high risk), who underwent chlamydia testing in the context of various diagnostic assays used over this time period. Assays utilised included culture, enzyme immunoassay (EIA), DNA probe, and nucleic acid amplification testing (NAAT). Non-parametric test for trend was used to determine significant differences between prevalence estimates across ordered groups. Least squares regression was conducted to describe a linear trend matching known data points.

RESULTS

Overall, there was no significant change for chlamydia prevalence which was 2.2%, in the 30-year study period (P = 0.7). Over time diagnostic assays changed from culture, to EIA, DNA probe, to the more sensitive NAAT. The bulk of the positives were in women under 25 years of age (57%).

CONCLUSION

Chlamydia prevalence has been stable over 30 years, remaining a problem in young women. Screening for those at risk needs underscoring in a national sexual health program.

Testing for chlamydial infection: are we meeting clinical guidelines? Evidence from a state-level laboratory data linkage analysis for 15- to 29-year-olds

Background Clinical guidelines recommend annual chlamydia tests for all sexually active people aged 15-29 years. This study measured adherence to these guidelines and compared testing rates to the projected levels required to reduce chlamydia prevalence.

METHODS

All chlamydia tests conducted in Tasmania during 2012-13, for residents aged 15-29 years, were linked. Data linkage allowed individuals who had multiple tests across different healthcare settings to be counted only once each year in analyses. Rates of testing and test positivity by age, sex, rebate status and socioeconomic indicators were measured.

RESULTS

There were 31899 eligible tests conducted in 24830 individuals. Testing coverage was higher in females (21%, 19404/92685) than males (6%, 5426/98123). Positivity was higher in males (16%, 862/5426) than females (10%, 1854/19404). Most tests (81%, 25803/31899) were eligible for a rebate. Positivity was higher in females with non-rebatable tests (12%, 388/3116 compared with those eligible for a rebate (9%, 1466/16285). More testing occurred in areas of middle disadvantage (10%, 9688/93678) compared with least (8%, 1680/21670) and most (10%, 7284/75460) (both P<0.001) disadvantaged areas. Higher test positivity was found in areas of most-disadvantage (11%, 822/7284) compared with middle- (10%, 983/9688) and least- (8%, 139/1680) disadvantaged areas.

CONCLUSIONS

Chlamydia testing rates are lower than recommended levels. Sustaining the current testing rates in females aged 20-24 years may reduce population prevalence within 10 years. This study meets key priorities of national strategies for chlamydia control by providing a method of monitoring testing coverage and evidence to evaluate prevention programs.

Correlates of sexually transmissible infection testing among a sample of at-risk young Australians

Annual chlamydia testing is recommended for all sexually active Australians aged 15-29 years; however, the testing rate is below recommended levels. Three surveys at a Melbourne music festival were conducted over 2012-14 to identify correlates of sexually transmissible infection (STI) testing among young people at risk of STIs. In total, 3588 participants were recruited; 72% reported having sex in the past year. Based on sexual behaviours, 38% of sexually active participants were classified as at risk of contracting STIs. In the past year, at-risk participants had significantly higher odds of reporting a STI test (37%) than participants classified as not at risk (24%) (OR=1.9; CI=1.6-2.3). Among at-risk participants, correlates of STI testing in the past year included being aged 20-24 years, visiting a GP, higher knowledge levels, earlier sexual debut and reporting more than five lifetime partners. Testing rates in our sample did not meet levels required to reduce chlamydia prevalence. However, the testing rate was higher in at-risk participants than participants who were not at risk. Future programs aiming to increase chlamydia testing should improve knowledge and promote the importance of testing after risk exposure, particularly among 16- to 19-year-olds.

Quadrivalent vaccine-targeted human papillomavirus genotypes in heterosexual men after the Australian female human papillomavirus vaccination programme: a retrospective observational study

BACKGROUND

Australia introduced a national quadrivalent human papillomavirus (4vHPV) vaccination programme for girls and young women in April, 2007. The HPV genotypes targeted by the female vaccine could also affect the protection afforded to heterosexual men. We examined the prevalence of 4vHPV targeted vaccine genotypes and the nine-valent HPV (9vHPV)-targeted vaccines genotypes among sexually active, predominantly unvaccinated heterosexual men from 2004 to 2015.

METHODS

We did a retrospective, observational study of urine and urethral swab specimens from heterosexual men aged 25 years or younger attending the Melbourne Sexual Health Centre between July 1, 2004, and June 30, 2015, who tested positive for Chlamydia trachomatis. We extracted HPV DNA and used the PapType HPV assay to detect 14 high-risk HPV genotypes (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68) and two low-risk genotypes (6 and 11). We calculated the prevalence of any HPV genotype, genotypes 6 or 11, genotypes 16 or 18, genotypes in the 4vHPV group (6, 11, 16, or 18), five additional genotypes in the 9vHPV group (31, 33, 45, 52, or 58), and non-vaccine-targeted genotypes (31, 33, 35, 39, 45, 51, 56, 58, 59, 66, or 68).

FINDINGS

We obtained data between July 1, 2004, and June 30, 2015, and did the data analysis in December, 2015. Of 1764 specimens obtained, we included 1466 in our final analysis (the others were excluded because they had indeterminate results or were duplicates). The prevalence of any HPV genotype and genotypes 31, 33, 45, 52, and 58 did not change from 2004-05 to 2014-15, but we noted reductions in genotypes 6 and 11 (from 12% [95% CI 6-21%], to 3% [1-7%], p_trend=0·008), 16 and 18 (from 13% [95% CI 7-22%] to 3% [1-6%], p_trend<0·0001), and 4vHPV-targeted genotypes (from 22% [95% CI 14-33%] to 6% [3-10%], p_trend<0·0001). Prevalence of non-vaccine-targeted genotypes increased from 16% [95% CI 9-26%] to 22% [17-29%], p_trend<0·0001). In Australian-born men, 4vHPV-targeted genotype prevalence decreased from 11 of 55 [20%, 95% CI 10-33%] to two of 74 [3%, 0-11%], p_trend<0·0001); an even greater decline occurred in Australian-born men aged 21 years or younger (from four of 13 [31%, 95% CI 9-61%] to none of 25; p_trend<0·0001). Genotypes 16 and 18 decreased (adjusted prevalence ratio [PR] 0·32, 95% CI 0·14-0·74; p=0·008) but not genotypes 6 and 11 (adjusted PR 0·50, 0·16-1·56; p=0·234) in the postvaccination period among men who had arrived in Australia within 2 years from countries with a bivalent vaccine (2vHPV) programme (England, Scotland, Wales, Cook Islands, Northern Ireland, or the Netherlands), compared with the prevaccination period. No change was noted in 4vHPV genotypes in men born overseas in other countries.

INTERPRETATION

The marked reduction in prevalence of 4vHPV genotypes among mainly unvaccinated Australian-born men suggests herd protection has occurred from the female vaccination programme. Additionally, the decline in genotypes 16 and 18, but not genotypes 6 and 11, among overseas-born men predominantly from countries with a 2vHPV vaccine programme suggests that these men received benefits from herd protection for genotypes 16 and 18 from their vaccinated female partners in their own countries. These reductions could translate to reductions in HPV-related malignant conditions in men, even in countries with female-only vaccination programmes.

FUNDING

The Australian National Health and Medical Research Council Program.

Exploration of testing practices and population characteristics support an increase in chlamydia positivity in Tasmania between 2001 and 2010

OBJECTIVE

The proportion of positive chlamydia tests in young people in Tasmania increased significantly between 2001 and 2010. While female positivity rates increased steadily, male positivity rose steeply to 2005 then stabilised. Crude positivity rates can be influenced by a variety of factors making interpretation difficult. Unique Tasmanian datasets were used to explore whether symptom status, reason for testing or sexual exposure could explain the observed positivity trends.

METHODS

Population-level chlamydia positivity rates in Tasmania over a 10-year period were compared with surveillance data collected on people aged 15 to 29 years notified with chlamydia.

RESULTS

The proportion of asymptomatic chlamydia cases increased, with the largest increase in males aged 15 to 19 years (28%). Opportunistic testing of cases increased (greatest in males, range 17-32%). Sexual exposure remained consistent.

CONCLUSIONS

After allowing for any changes in sexual exposure, symptom status and reason for testing, an increase in chlamydia positivity occurred over the 10 years. Healthcare providers have increased chlamydia testing in high-risk groups.

IMPLICATIONS

Monitoring chlamydia testing patterns and positivity rates at a population level is a step forward in surveillance practices. Targeted surveys provide valuable information to supplement routine surveillance data.

Young Risk Takers: Alcohol, Illicit Drugs, and Sexual Practices among a Sample of Music Festival Attendees

Background. Alcohol and other drug use and sexual risk behaviour are increasing among young Australians, with associated preventable health outcomes such as sexually transmissible infections (STIs) on the rise. Methods. A cross-sectional study of young people's health behaviours conducted at a music festival in Melbourne, Australia, in 2011. Results. 1365 young people aged 16–29 completed the survey; 62% were female with a mean age of 20 years. The majority (94%, n = 1287) reported drinking alcohol during the previous 12 months; among those, 32% reported “binge” drinking (6+ drinks) at least weekly. Half (52%) reported ever using illicit drugs and 25% reported past month use. One-quarter (27%) were identified as being at risk of STIs through unprotected sex with new or casual partners during the previous 12 months. Multivariable analyses found that risky sexual behaviour was associated with younger age (≤19 years), younger age of sexual debut (≤15 years), having discussed sexual health/contraception with a doctor, regular binge drinking, and recent illicit drug use. Conclusion. Substance use correlated strongly with risky sexual behaviour. Further research should explore young people's knowledge of alcohol/drug-related impairment and associated risk-taking behaviours, and campaigns should encourage appropriate STI testing among music festival attendees.

Fall in genital warts diagnoses in the general and indigenous Australian population following implementation of a national human papillomavirus vaccination program: analysis of routinely collected national hospital data

BACKGROUND

Human papillomavirus (HPV) vaccination targeting females aged 12-13 years commenced in Australia in 2007, with catch-up vaccination of females aged 13-26 years continuing to 2009. Whole-population analyses, including effects on the Indigenous population, have not previously been reported.

METHODS

All hospital admissions between 1999-2011 involving a diagnosis of genital warts were obtained from a comprehensive national database. We compared the age-specific rates before to those after implementation of the vaccination program, according to sex and other characteristics.

RESULTS

Admission rates decreased from mid-2007 in females aged 12-17 years (annual decline, 44.1% [95% confidence interval {CI}, 35.4%-51.6%]) and from mid-2008 in females and males aged 18-26 years (annual declines, 31.8% [95% CI, 28.4%-35.2%] and 14.0% [95% CI, 5.1%-22.1%], respectively). The overall reductions from 2006-2007 to 2010-2011 were 89.9% (95% CI, 84.4%-93.4%) for females aged 12-17 years, 72.7% (95% CI, 67.0%-77.5%) for females aged 18-26 years, and 38.3% (95% CI, 27.7%-47.2%) for males aged 18-26 years. Compared with the average annual number before program implementation, about 1000 fewer hospital admissions involved a warts diagnosis during 2010-2011. Reductions after program implementation were similar for Indigenous (86.7% [95% CI, 76.0-92.7]) and non-Indigenous (76.1% [95% CI, 71.6%-79.9%]) females aged 15-24 years (P(heterogeneity) = .08).

CONCLUSIONS

National population-based hospital data confirm previous clinic-based reports of a marked decline in genital warts diagnoses among young people in Australia after program implementation, including indirect benefits to males. The impact of HPV vaccination appears to be similar in young Indigenous and non-Indigenous females.

Epidemiology of gonorrhoea notifications in Australia, 2007-12

Background An increase in the notification rate of gonorrhoea was observed in the national surveillance system. In Australia, gonorrhoea is relatively rare, apart from among some populations of Aboriginal people and men who have sex with men.

METHODS

Data about gonorrhoea cases reported between 2007 and 2012 from all Australian jurisdictions were extracted from the National Notifiable Diseases Surveillance System. Analyses were undertaken of the time trends in counts and rates, according to jurisdiction, gender, Aboriginal and Torres Strait Islander status, diagnosis method and sexual orientation.

RESULTS

The largest increase in notifications between 2007 and 2012 was observed in both men and women in New South Wales (2.9- and 3.7-fold greater in 2012 than 2007, respectively) and Victoria (2.4- and 2.7-fold greater in 2012 than 2007, respectively), men in the Australian Capital Territory and women in Queensland. The highest notification rates remained in Indigenous people in the Northern Territory and Western Australia, and particularly in women, although rates may have decreased over the study period. Changes in age and sex distribution, antimicrobial resistance and patterns of exposure and acquisition were negligible.

CONCLUSIONS

There is an ongoing gonorrhoea epidemic affecting Aboriginal and Torres Strait Islander people in Australia, but the increases in notifications have occurred primarily in non-Aboriginal populations in the larger jurisdictions. Interpretation of these surveillance data, especially in relation to changes in population subgroups, would be enhanced by laboratory testing data. Further efforts are needed to decrease infection rates in populations at highest risk.