HIV incidence in Indigenous and non-Indigenous populations in Australia: a population-level observational study.

BACKGROUND: Australia has set a national target of ending HIV by 2020, achieving this will require the inclusion of priority populations (eg, Indigenous Australians) in strategies to reach elimination. To assist in evaluating the target of elimination, we analysed HIV notification data for Indigenous and non-Indigenous Australians. METHODS: Using the National HIV Registry at The Kirby Institute at UNSW, Sydney, NSW, Australia, we collated and analysed annual HIV notification data for 1996-2015. Patients who were not born in Australia were excluded. We calculated the rates of HIV diagnoses with annual trends in notification rates for Indigenous versus non-Indigenous Australians by demographic characteristics, exposure categories, and stage of HIV at diagnosis. For missing data, assumptions were made and verified through sensitivity analyses. Annual rate ratio (RR) and 4 year summary rate ratio (SRR) trends were calculated to determine patterns of HIV diagnosis in the two populations. FINDINGS: Between Jan 1, 1996, and Dec 31, 2015, 11 492 people born in Australia were reported with a diagnosis of HIV, of whom 461 (4%) were recorded as Indigenous Australians and we classified the remaining 11 031 (96%) as non-Indigenous Australians. For exposure to HIV, among Indigenous Australians a higher proportion of diagnoses occurred among women, and through injecting drug use and heterosexual sex than among non-Indigenous Australians (p<0·0001). Among Indigenous Australians, we found a significantly higher SRR of HIV diagnoses among men in the period 2012-15 than in previous periods (SRR 1·53, 95% CI 1·28-1·83; p<0·0001), and significantly higher diagnosis among Indigenous women (4·92, 4·02-6·02; p<0·0001) for the entire study period than among non-Indigenous women. Concurrently, a decrease in HIV diagnoses of 1% per annum (RR 0·99, 95% CI 0·98-0·99; p<0·0001) across the study period was seen among non-Indigenous people. Indigenous Australians were more likely to be diagnosed at an advanced stage of HIV infection than non-Indigenous Australians (20·8% vs 15·1%; p=0·0088). INTERPRETATION: Greater efforts should be made to include Indigenous people in prevention strategies, particularly newer biomedical interventions, such as scale up of pre-exposure prophylaxis and treatment as prevention initiatives in Australia. More involvement of Indigenous Australians in these approaches is also required to prevent widening of the gap in HIV diagnosis rates between non-Indigenous and Indigenous Australians. FUNDING: None.

Using record linkage to validate notification and laboratory data for a more accurate assessment of notifiable infectious diseases.

BACKGROUND: Infectious disease burden is commonly assessed using notification data. Using retrospective record linkage in Western Australia, we described how well notification data captures laboratory detections of influenza, pertussis and invasive pneumococcal disease (IPD). METHODS: We linked data from the Western Australian Notifiable Infectious Diseases Database (WANIDD) and the PathWest Laboratory Database (PathWest) pertaining to the Triple I birth cohort, born in Western Australia in 1996-2012. These were combined to calculate the number of unique cases captured in each dataset alone or in both datasets. To assess the impact of under-ascertainment, we compared incidence rates calculated using WANIDD data alone and using combined data. RESULTS: Overall, there were 5550 influenza, 513 IPD (2001-2012) and 4434 pertussis cases (2000-2012). Approximately 2% of pertussis and IPD cases and 7% of influenza cases were solely recorded in PathWest. Notification of influenza and pertussis cases to WANIDD improved over time. Overall incidence rates of influenza in children aged <5 years using both datasets was 10% higher than using WANIDD data alone (IRR = 1.1, 95% CI = 1.1-1.2). CONCLUSIONS: This is the first time WANIDD data have been validated against routinely collected laboratory data. We anticipated all cases would be captured in WANIDD but found additional laboratory-confirmed cases that were not notified. Studies investigating pathogen-specific infectious disease would benefit from using multiple data sources.

Syphilis epidemiology and public health interventions in Western Australia from 1991 to 2009.

OBJECTIVES: To describe the epidemiology of congenital and infectious syphilis during 1991-2009, examine the impact of public health interventions and discuss the feasibility of syphilis elimination among Aboriginal people in Western Australia (WA). METHODS: WA congenital and infectious syphilis notification data in 1991-2009 and national infectious syphilis notification data in 2005-2009 were analysed by Aboriginality, region of residence, and demographic and behavioural characteristics. Syphilis public health interventions in WA from 1991-2009 were also reviewed. RESULTS: During 1991-2009, there were six notifications of congenital syphilis (50% Aboriginal) and 1441 infectious syphilis notifications (61% Aboriginal). During 1991-2005, 88% of notifications were Aboriginal, with several outbreaks identified in remote WA. During 2006-2009, 62% of notifications were non-Aboriginal, with an outbreak in metropolitan men who have sex with men. The Aboriginal:non-Aboriginal rate ratio decreased from 173:1 (1991-2005) to 15:1 (2006-2009). CONCLUSIONS: These data demonstrate that although the epidemiology of syphilis in WA has changed over time, the infection has remained endemic among Aboriginal people in non-metropolitan areas. Given the continued public health interventions targeted at this population, the limited success in eliminating syphilis in the United States and the unique geographical and socioeconomic features of WA, the elimination of syphilis seems unlikely in this state.