Impact of Meningococcal ACWY Vaccination Program during 2017-18 Epidemic, Western Australia, Australia.

The rising incidence of invasive meningococcal disease (IMD) caused by Neisseria meningitidis serogroup W in Western Australia, Australia, presents challenges for prevention. We assessed the effects of a quadrivalent meningococcal vaccination program using 2012-2020 IMD notification data. Notification rates peaked at 1.8/100,000 population in 2017; rates among Aboriginal and Torres Strait Islander populations were 7 times higher than for other populations. Serogroup W disease exhibited atypical manifestations and increased severity. Of 216 cases, 20 IMD-related deaths occurred; most (19/20) were in unvaccinated persons. After the 2017-2018 targeted vaccination program, notification rates decreased from 1.6/100,000 population in 2018 to 0.9/100,000 population in 2019 and continued to decline in 2020. Vaccine effectiveness (in the 1-4 years age group) using the screening method was 93.6% (95% CI 50.1%-99.2%) in 2018 and 92.5% (95% CI 28.2%-99.2%) in 2019. Strategic planning and prompt implementation of targeted vaccination programs effectively reduce IMD.

Travel-associated lineages and unique endemic antimicrobial-susceptible lineages of Neisseria gonorrhoeae predominate in Western Australia.

In Australia, gonococcal isolates are monitored for antimicrobial susceptibilities. In Western Australia (WA), gonorrhoea notification rates increased by 63 % between 2013 and 2016, with the steepest increase occurring between 2015 and 2016, before stabilizing at this higher baseline between 2017 and 2020. This increased prevalence was associated with antimicrobial-susceptible (AMS) lineages. To understand the provenance of these isolates causing gonorrhoea in WA, whether they were introduced or expanded from endogenous lineages, 741 isolates were collected in 2017 and characterized by both iPLEX typing and whole genome sequencing (WGS). Antibiograms and genocoding of the isolates revealed that AMS isolates were most prevalent in the remote regions, while the urban/rural regions were characterized by antimicrobial-resistant (AMR) isolates. iPLEX typing identified 78 iPLEX genotypes (WA-1 to WA-78) of which 20 accounted for over 88 % of isolates. WA-10 was the most frequently identified genotype in the urban/rural regions whilst WA-29 was the most frequently identified genotype in the remote regions. Genotypes WA-38, WA-52 and WA-13 accounted for 81 % (n=36/44) of the azithromycin-resistant N. gonorrhoeae (AziR) isolates. A representative isolate of each iPLEX genotype and AMR biotype was whole genome sequenced and analysed using MLST, NG-MAST and NG-STAR, and the novel core genome clustering Ng_cgc_400 typing scheme. Five predominant Bayesian population groups (termed BPG-1 to 5) were identified in the study collection. BPG-1 and BPG-2 were associated with AMS isolates from the remote regions. BPG-1 and BPG-2 were shown to be unique to the remote regions based on a minimum spanning tree against 4000 international isolates. AMS isolates in urban/rural regions were dominated by international lineages. AziR and Cef DS (decreased susceptibility to ceftriaxone) was concentrated in three urban/rural genomic groups (BPG-3, 4 and 5). Azithromycin minimum inhibitory concentrations (0.5-16 mg l-1) correlated with the accumulation of mtrR mutations or/and the fraction of 23S rRNA C2611T mutated copies. The majority of isolates in BPG-3, 4 and 5 could be correlated with known AMR lineages circulating globally and nationally. In conclusion, the surge in AMS isolates in WA in 2017 was due to importation of international AMS lineages into urban/rural regions, whilst the local AMS lineages persisted largely in the remote regions. Bridging between the urban/rural and remote regions was relatively rare, but continued surveillance is required to prevent ingress of AMR strains/lineages into the remote regions of WA.

Trends in late and advanced HIV diagnoses among migrants in Australia; implications for progress on Fast-Track targets: A retrospective observational study.

Achieving the Joint United Nations Program on human immunodeficiency virus (HIV)/AIDS Fast-Track targets requires additional strategies for mobile populations. We examined trends and socio-demographics of migrants (overseas-born) and Australian-born individuals presenting with late and advanced HIV diagnoses between 2008 and 2017 to help inform public health approaches for HIV testing coverage and linkage to care and treatment.We conducted a retrospective population-level observational study of individuals diagnosed with HIV in Australia and reported to the National HIV Registry. Annual proportional trends in late (CD4+ T-cell count <350 cells/µL) and advanced (CD4+ T-cell count <200 cells/µL). HIV diagnoses were determined using Poisson regression.Of 9926 new HIV diagnoses from 2008 to 2017, 84% (n = 8340) were included in analysis. Overall, 39% (n = 3267) of diagnoses were classified as late; 52% (n = 1688) of late diagnoses were advanced. Of 3317 diagnoses among migrants, 47% were late, versus 34% of Australian-born diagnoses (P < .001).The annual proportions of late (incidence rate ratio [IRR] 1.00; 95% confidence interval [CI] 0.99-1.01) and advanced HIV diagnoses (IRR 1.01; 95% CI 0.99-1.02) remained constant. Among migrants with late HIV diagnosis, the proportion reporting male-to-male sex exposure (IRR 1.05; 95% CI 1.03-1.08), non-English speaking (IRR 1.03; 95% CI 1.01-1.05), and individuals born in countries in low HIV-prevalence (IRR 1.02; 95% CI 1.00-1.04) increased. However, declines were noted among some migrants' categories such as females, heterosexual exposure, English speaking, and those born in high HIV-prevalence countries.Late HIV diagnosis remains a significant public health concern in Australia. Small declines in late diagnosis among some migrant categories are offset by increases among male-to-male exposures. Reaching the Fast-Track targets in Australia will require targeted testing and linkage to care strategies for all migrant populations, especially men who have sex with men.

Long-term Impact of Pneumococcal Conjugate Vaccines on Invasive Disease and Pneumonia Hospitalizations in Indigenous and Non-Indigenous Australians.

BACKGROUND: Universal pneumococcal conjugate vaccine (PCV) programs began in Indigenous Australian children in 2001 and all children in 2005, changing to 13-valent PCV (PCV13) in 2011. We used laboratory data for invasive pneumococcal disease (IPD) and coded hospitalizations for noninvasive pneumococcal community-acquired pneumonia (PnCAP) to evaluate long-term impact. METHODS: Annual incidence (per 100 000 population) was calculated for age-specific total IPD, PCV13 non-7-valent PCV (PCV7) serotypes, and PnCAP by Indigenous status. Incidence in the pre-universal PCV7 (2002-2004), early PCV7 (2005-2007), pre-PCV13 (2008 to mid-2011), and post-PCV13 (mid-2011 to 2016) periods was used to calculate incidence rate ratios (IRRs). RESULTS: In the total population, all-age incidence of IPD declined from 11.8 pre-PCV7 to 7.1 post-PCV13 (IRR, 0.61 [95% confidence interval {CI}, .59-.63]) but for PnCAP declined among ages <1 year (IRR, 0.34 [95% CI, .25-.45]) and 1-4 years (IRR, 0.50 [95% CI, .43-.57]) but increased significantly among age ≥5 years (IRRs, 1.08-1.14). In Indigenous people, baseline PCV13 non-PCV7 IPD incidence was 3-fold higher, amplified by a serotype 1 epidemic in 2011. By 2015-2016, although incidence of IPD and PnCAP in children aged <5 years decreased by 38%, neither decreased in people aged ≥5 years. CONCLUSIONS: Fifteen years post-PCV and 5 years post-PCV13, direct and indirect impact on IPD and PnCAP differed by age and between Indigenous and non-Indigenous people, with potential implications for long-term PCV impact in comparable settings.Fifteen years after pneumococcal conjugate vaccine (PCV) introduction and 5 years post-PCV13, direct and indirect impact on invasive pneumococcal disease and pneumococcal community-acquired pneumonia differed by age and between Indigenous and non-Indigenous people, with potential implications for long-term PCV impact in comparable settings.

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.

Pretravel Health Advice Among Australians Returning From Bali, Indonesia: A Randomized Controlled Trial Protocol.

BACKGROUND: The effect of pretravel health advice (PTHA) on travel-related illness rates is poorly understood, and to date there are no published randomized controlled trials evaluating the impact of PTHA outcomes. OBJECTIVE: This study aims to determine the effect of an online PTHA intervention on travel-related illness rates in Western Australians visiting Bali, Indonesia. METHODS: Western Australian travelers to Bali will be recruited online before departure and will be randomly allocated to an intervention or control group by computer algorithm. The intervention in this study is a short animated video, with accompanying text, containing PTHA relevant to Bali. An online posttravel survey will be administered to all participants within two weeks of their return from Bali. The primary outcome is the difference in self-reported travel-related illness rates between control and intervention groups. Secondary outcomes include the difference in risk prevention behaviors and health risk knowledge between the control and intervention groups. Further secondary outcomes include whether individuals in the control group who sought external PTHA differ from those who did not with respect to risk prevention behaviors, health risk knowledge, and health risk perception, as well as the rate of self-reported travel-related illness. RESULTS: The study began recruitment in September 2016 and will conclude in September 2017. Data analysis will take place in late 2017, with results disseminated via peer-reviewed journals in early 2018. CONCLUSIONS: This will be the first randomized controlled trial to examine the effect of a novel PTHA intervention upon travel-related illness. In addition, this study builds upon the limited existing data on the effectiveness of PTHA on travel-related illness. CLINICALTRIAL: Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12615001230549; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=369567 (Archived by WebCite at http://www.webcitation.org/6m0G7xJg1).

Health Seeking Behaviours and Knowledge of Infectious Disease Risks in Western Australian Travellers to Southeast Asian Destinations: An Airport Survey.

As the number of Australians engaging in short-term international travel increases, so does the opportunity for importing overseas-acquired infectious diseases. This study aimed to determine knowledge of infectious disease risks and pre-travel health advice (PTHA) seeking behaviour among Western Australians travelling to Bali, Indonesia or Thailand. Passengers departing from Perth International Airport were invited to participate in a self-administered survey. The survey determined PTHA seeking behaviour, knowledge of specific disease risks, and expected disease-prevention behaviours abroad. Multivariate regression modelling was used to assess demographic and travel-related factors associated with seeking PTHA. Responses from 1334 travellers were analysed. The proportion correctly identifying specific overseas disease risks ranged from 27% to 98%. High levels of planned disease-preventive behaviours were reported; however only 32% of respondents sought PTHA for their trip, most commonly from friends/family (15%) or a GP (14%). Many travellers (87%) made online travel purchases, but few (8%) used the Internet to source PTHA. WA travellers to Bali and Thailand were unlikely to seek PTHA and knowledge varied regarding infectious disease risks associated with travel. High rates of internet use when planning travel may provide an opportunity for destination-specific health promotion messaging and should be explored.

Evaluation of impact of 23 valent pneumococcal polysaccharide vaccine following 7 valent pneumococcal conjugate vaccine in Australian Indigenous children.

BACKGROUND: High incidence and serotype diversity of invasive pneumococcal disease (IPD) in Indigenous children in remote Australia led to rapid introduction of 7-valent conjugate pneumococcal vaccine (7vPCV) at 2, 4 and 6 months in 2001, followed by 23-valent polysaccharide pneumococcal vaccine (23vPPV) in the second year of life. All other Australian children were offered 3 doses of 7vPCV without a booster from 2005. This study evaluated the impact of the unique pneumococcal vaccine schedule of 7vPCV followed by the 23vPPV booster among Indigenous Australian children. METHODS: Changes in IPD incidence derived from population-based passive laboratory surveillance in Indigenous children <5 years eligible for 23vPPV were compared to non-Indigenous eligible for 7vPCV only from the pre-vaccine introduction period (Indigenous 1994-2000; non-Indigenous 2002-2004) to the post-vaccine period (2008-2010 in both groups) using incidence rate ratios (IRRs) stratified by age into serotype groupings of vaccine (7v and 13vPCV and 23vPPV) and non-vaccine types. Vaccine coverage was assessed from the Australian Childhood Immunisation Register. RESULTS: At baseline, total IPD incidence per 100,000 was 216 (n=230) in Indigenous versus 55 (n=1993) in non-Indigenous children. In 2008-2010, IRRs for 7vPCV type IPD were 0.03 in both groups, but for 23v-non7v type IPD 1.2 (95% CI 0.8-1.8) in Indigenous versus 3.1 (95% CI 2.5-3.7) in non-Indigenous, difference driven primarily by serotype 19A IPD (IRR 0.6 in Indigenous versus 4.3 in non-Indigenous). For non-7vPCV type IPD overall, IRR was significantly higher in those age-eligible for 23vPPV booster compared to those younger, but in both age groups was lower than for non-Indigenous children. CONCLUSION: These ecologic data suggest a possible "serotype replacement sparing" effect of 23vPPV following 7vPCV priming, especially for serotype 19A with supportive evidence from other immunogenicity and carriage studies. Applicability post 10vPCV or 13v PCV priming in similar settings would depend on local serotype distribution of IPD.

Investigation of the First Case of Dengue Virus Infection Acquired in Western Australia in Seven Decades: Evidence of Importation of Infected Mosquitoes?

In October 2013, a locally-acquired case of dengue virus (DENV) infection was reported in Western Australia (WA) where local dengue transmission has not occurred for over 70 years. Laboratory testing confirmed recent DENV infection and the case demonstrated a clinically compatible illness. The infection was most likely acquired in the Pilbara region in the northwest of WA. Follow up investigations did not detect any other locally-acquired dengue cases or any known dengue vector species in the local region, despite intensive adult and larval mosquito surveillance, both immediately after the case was notified in October 2013 and after the start of the wet season in January 2014. The mechanism of infection with DENV in this case cannot be confirmed. However, it most likely followed a bite from a single infected mosquito vector that was transiently introduced into the Pilbara region but failed to establish a local breeding population. This case highlights the public health importance of maintaining surveillance efforts to ensure that any incursions of dengue vectors into WA are promptly identified and do not become established, particularly given the large numbers of viraemic dengue fever cases imported into WA by travellers returning from dengue-endemic regions.

Early diagnosis of HIV among men who have sex with men in Western Australia: impact of a peer-led sexually transmissible infection testing service.

UNLABELLED: Background In July 2010, the Western Australian AIDS Council established the 'M Clinic', a peer-led STI testing service for MSM. This study describes trends in HIV notifications among MSM in WA from 2004 to 2013, particularly the impact of the M Clinic on newly acquired HIV diagnoses. METHODS: The number and proportion of MSM HIV cases with newly acquired infection were compared for the 2004-2006, 2007-2009 and 2011-2013 time periods. Data from 2010 were excluded as the M Clinic opened in July 2010. RESULTS: Between the 2004-2006 and 2007-2009 periods, the number of MSM with newly acquired HIV increased by 50% (23 to 33 cases) and the number of newly acquired cases as a proportion of all new HIV diagnoses among MSM increased from 27% to 35% (30% increase) (P=0.25). In the 2011-2013 period, the number of newly acquired HIV cases among MSM more than doubled to 70 cases and comprised 53% of all new HIV diagnoses among MSM (P<0.05). Of the 70 newly acquired HIV cases in the 2011-2013 period, 30% (n=21) were diagnosed at the M Clinic. CONCLUSIONS: The proportion of MSM HIV notifications that were newly acquired increased between 2004 and 2013 in WA, with the greatest increase seen after the M Clinic commenced operation. A peer-led approach to HIV testing should be considered in order to achieve early diagnosis and treatment of HIV among MSM.

Risk factors and comorbidities for invasive pneumococcal disease in Western Australian Aboriginal and non-Aboriginal people.

Australian Aboriginal people have among the highest rates of invasive pneumococcal disease (IPD) worldwide. We investigated clinical diagnosis, risk factors, comorbidities and vaccine coverage in Aboriginal and non-Aboriginal IPD cases. Using enhanced surveillance, we identified IPD cases in Western Australia, Australia, between 1997 and 2007. We calculated the proportion with risk factors and comorbidities in children (<5 years) and adults (=15 years), as well as adults living in metropolitan and non-metropolitan regions. We then calculated the proportion of cases eligible for vaccination who were vaccinated before contracting IPD. Of the 1,792 IPD cases that were reported, 355 (20%) were Aboriginal and 1,155 (65%) were adults. Pneumonia was the most common diagnosis (61% of non-Aboriginal and 49% of Aboriginal adult IPD cases in 2001-2007). Congenital abnormality was the most frequent comorbidity in non-Aboriginal children (11%). In Aboriginal children, preterm delivery was most common (14%). Ninety-one percent of non-Aboriginal and 96% of Aboriginal adults had one or more risk factors or comorbidities. In non-Aboriginal adults, cardiovascular disease (34%) was the predominant comorbidity whilst excessive alcohol use (66%) was the most commonly reported risk factor in Aboriginal adults. In adults, comorbidities were more frequently reported among those in metropolitan regions than those in non-metropolitan regions. Vaccination status was unknown for 637 of 1,082 cases post-July 2001. Forty-one percent of non-Aboriginal and 60% of Aboriginal children were eligible for vaccination but were not vaccinated. Among adults with risk factors who were eligible for vaccination and with known vaccination status, 75% Aboriginal and 94% non-Aboriginal were not vaccinated. An all-of-life immunisation register is needed to evaluate vaccine coverage and effectiveness in preventing IPD in adults.

Aboriginal and non-Aboriginal sexually transmitted infections and blood borne virus notification rates in Western Australia: using linked data to improve estimates.

BACKGROUND: National notification data for sexually transmitted infections (STIs) and blood borne viruses (BBVs) continue to have a high proportion of missing data on Indigenous status, potentially biasing estimates of notification rates by Aboriginality. We evaluated the use of data linkage to improve the accuracy of estimated notification rates for STIs and BBVs in Aboriginal and non-Aboriginal groups in Western Australia. METHODS: STI and BBV case notifications in Western Australia received in 2010 were linked with administrative health data collections in Western Australia to obtain additional data on Indigenous status. STI and BBV notification rates based on the pre- and post-linkage data among Aboriginal and non-Aboriginal groups were compared. RESULTS: Data linkage decreased the proportion of notifications with unknown Indigenous status by 74% from 10.2% to 2.7%. There was no significant difference in disease-specific age-adjusted notification rate ratio estimates based on pre-linkage data and post-linkage data for Aboriginal people compared with non-Aboriginal people. CONCLUSION: Our findings suggest that reported STI and BBV disease-specific age-adjusted notification rates for 2010 in Western Australia are unlikely to be significantly biased by excluding notifications with unknown Indigenous status. This finding is likely to be dependent on recent improvements in the reporting of Indigenous status in notification data in Western Australia. Cost-effective and systematic solutions, including the better use of existing data linkage resources, are required to facilitate continued improvement in the completeness of reporting and accuracy of estimates for notifiable STIs and BBVs in Australia by Aboriginality.

Improvement in antenatal testing for sexually transmissible infections and blood-borne viruses in Western Australian hospitals, 2007 to 2010.

OBJECTIVE: Antenatal testing for specified sexually transmissible infections (STIs) and blood-borne viruses (BBVs) is recommended by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). In 2007, the Department of Health, Western Australia (DoHWA) issued an operational directive (OD) recommending universal testing for chlamydia and additional testing for women in the STI endemic regions of Western Australia (WA). To assess adherence to these guidelines, seven WA public hospitals were audited. DESIGN AND SETTING: Demographic details and testing information of the last 200 women who gave birth immediately before 30 June 2007 (baseline audit) and 30 June 2010 (follow-up audit) were obtained from each hospital's antenatal records. RESULTS: Data from 2718 women who delivered at ≥36 weeks' gestation were analysed (baselinen=1353; follow-upn=1365). Testing at the first antenatal visit in accordance with the guidelines improved over time (RANZCOG: 68-74%; χ(2)-test = 13.96, d.f.=1, P<0.001; DoHWA OD: 12-40%; χ(2)-test = 279.71, d.f.=1, P<0.001). Retesting at 28-36 weeks' gestation in the STI endemic regions improved for chlamydia (3-10%; χ(2)-test = 17.40, d.f.=1, P<0.001) and gonorrhoea (3-7%; χ(2)-test=6.62, d.f.=1, P<0.05), but not for syphilis or HIV. Chlamydia prevalence was 3% and 8% among nonAboriginal and Aboriginal women, respectively. CONCLUSION: The proportion of women delivering in WA public hospitals who had antenatal STI and BBV tests improved after publication and promotion of the OD.

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.

Chronic disease and hospitalisation for pandemic (H1N1) 2009 influenza in Indigenous and non-Indigenous Western Australians.

Indigenous and non-indigenous Western Australians with pandemic (H1N1) 2009 influenza (pH1N1) infection were compared for risk factors, influenza vaccination history, symptoms, use of antiviral medications, and hospitalisation. Data were collected systematically on 856 notified cases with laboratory confirmed pH1N1 infection during the first 10 weeks of pH1N1 virus transmission in Western Australia in 2009. Indigenous people with pH1N1 were approximately 3 times more likely to be hospitalised and were more likely to have a range of underlying medical conditions and be smokers, compared with non-Indigenous cases. Age (P < 0.001) and the presence of two or more co-morbidities (P < 0.001) were independent predictors of hospitalisation, while Indigenous status was not, indicating that higher pH1N1 hospitalisation rates in Indigenous Australians during the 2009 winter season were attributable to the higher prevalence of underlying chronic disease. These results underscore the need to ensure that influenza vaccination is delivered as widely as possible among those with chronic health conditions.

Epidemiology of syphilis in Australia: moving toward elimination of infectious syphilis from remote Aboriginal and Torres Strait Islander communities?

OBJECTIVE: To describe the epidemiology of infectious syphilis among Aboriginal and Torres Strait Islander (Indigenous) people in Australia. DESIGN AND SETTING: We assessed trends in national infectious syphilis notification rates from 2005 to 2009 using Poisson regression, with a focus on geographic and demographic differences by Indigenous status. We compared Indigenous and non-Indigenous rate ratios over the study period and summarised the annual changes (summary rate ratio). MAIN OUTCOME MEASURES: Crude notification rates and summary rate ratios by Indigenous status, jurisdiction, sex, age group and area of residence. RESULTS: From 2005 to 2009, in the Indigenous population, there was a substantial decline in the notification rate for infectious syphilis nationally; as well as in the following subgroups: females, 15-29 year olds, and people living in outer regional and remote areas in the Northern Territory and Queensland. In contrast, there was a significant (P < 0.001) upward trend in the notification rate in the non-Indigenous population nationally; as well as in males, in people aged 20 years and over, and in residents of metropolitan and regional areas, New South Wales, Queensland, South Australia, Victoria and Western Australia. The highest summary rate ratios were seen in remote/very remote areas (86.33; 95% CI, 57.45-129.74), in 15-19 year olds (64.65; 95% CI, 51.12-81.78), in females (24.59; 95% CI, 19.73-30.65), and in Western Australia (23.89; 95% CI, 19.82-28.82). CONCLUSION: These data demonstrate that Australia has two distinct patterns of infectious syphilis: a substantially declining occurrence in Indigenous remote communities and an increasing incidence in males residing in urban and regional areas. Given the decline in notification rates in Indigenous remote communities, now might be the right time to move toward eliminating infectious syphilis from Indigenous communities.

Comparison of pandemic (H1N1) 2009 and seasonal influenza, Western Australia, 2009.

We compared confirmed pandemic (H1N1) 2009 influenza and seasonal influenza diagnosed in Western Australia during the 2009 influenza season. From 3,178 eligible reports, 984 pandemic and 356 seasonal influenza patients were selected; 871 (88.5%) and 288 (80.9%) were interviewed, respectively. Patients in both groups reported a median of 6 of 11 symptoms; the difference between groups in the proportion reporting any given symptom was < or =10%. Fewer than half the patients in both groups had > or =1 underlying condition, and only diabetes was associated with pandemic (H1N1) 2009 influenza (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.1-3.5). A total of 129 (14.8%) persons with pandemic (H1N1) 2009 and 36 (12.5%) persons with seasonal influenza were hospitalized (p = 0.22). After controlling for age, we found that patient hospitalization was associated with pandemic (H1N1) 2009 influenza (OR 1.5; 95% CI 1.1-2.1). Contemporaneous pandemic and seasonal influenza infections were substantially similar in terms of patients' symptoms, risk factors, and proportion hospitalized.

The changing epidemiology of invasive pneumococcal disease in aboriginal and non-aboriginal western Australians from 1997 through 2007 and emergence of nonvaccine serotypes.

BACKGROUND. In 2001, Australia introduced a unique 7-valent pneumococcal conjugate vaccine (7vPCV) 2-, 4-, and 6-month schedule with a 23-valent pneumococcal polysaccharide vaccine (23vPPV) booster for Aboriginal children, and in 2005, 7vPCV alone in a 2-, 4-, and 6-month schedule for non-Aboriginal children. Aboriginal adults are offered 23vPPV but coverage is poor. We investigated trends in invasive pneumococcal disease (IPD) in Western Australia (WA). METHODS. Enhanced IPD surveillance has been ongoing since 1996. We calculated IPD incidence rates for Aboriginal and non-Aboriginal Australians before and after introduction of 7vPCV. RESULTS. A total of 1792 cases occurred during the period 1997-2007; the IPD incidence rate was 47 cases per 100,000 population per year among Aboriginal people and 7 cases per 100,000 population per year in non-Aboriginal people. After introduction of 7vPCV, IPD rates among Aboriginal children decreased by 46% for those <2 years of age and by 40% for those 2-4 years of age; rates decreased by 64% and 51% in equivalent age groups for non-Aboriginal children. IPD rates decreased by >30% in non-Aboriginal people 50 years of age but increased among Aboriginal adults (eg, from 59.1 to 109.6 cases per 100,000 population per year among those 30-49 years of age). Although IPD due to 7vPCV serotypes decreased in all age groups, IPD incidence due to non-7vPCV serotypes increased, and it almost doubled among Aboriginal adults 30-49 years of age (from 48.3 to 97.0 cases per 100,000 population per year). Among non-Aboriginal children, 37% of IPD is now due to serotype 19A. CONCLUSIONS. IPD incidence rates have decreased markedly among children and non-Aboriginal adults with a 3-dose infant 7vPCV schedule. However, IPD due to non-7vPCV serotypes has increased and is of particular concern among young Aboriginal adults, for whom an intensive 23vPPV campaign is needed. An immunization register covering all age groups should be established.

Household responses to pandemic (H1N1) 2009-related school closures, Perth, Western Australia.

School closure is often purported to reduce influenza transmission, but little is known about its effect on families. We surveyed families affected by pandemic (H1N1) 2009-related school closures in Perth, Western Australia, Australia. Surveys were returned for 233 (58%) of 402 students. School closure was deemed appropriate by 110 parents (47%); however, 91 (45%) parents of 202 asymptomatic students reported taking >or=1 day off work to care for their child, and 71 (35%) had to make childcare arrangements because of the class closures. During the week, 172 (74%) students participated in activities outside the home on >or=1 occasion, resulting in an average of 3.7 out-of-home activities for each student. In our survey, activities outside the home were commonly reported by students affected by school closure, the effect on families was substantial, and parental opinion regarding school closures as a means to mitigate the outbreak of pandemic (H1N1) 2009 was divided.