Doherty Institute - Research Publications
Now showing items 1-12 of 147
Epidemiological consequences of enduring strain-specific immunity requiring repeated episodes of infection
(PUBLIC LIBRARY SCIENCE, 2020-06-01)
Group A Streptococcus (GAS) skin infections are caused by a diverse array of strain types and are highly prevalent in disadvantaged populations. The role of strain-specific immunity in preventing GAS infections is poorly understood, representing a critical knowledge gap in vaccine development. A recent GAS murine challenge study showed evidence that sterilising strain-specific and enduring immunity required two skin infections by the same GAS strain within three weeks. This mechanism of developing enduring immunity may be a significant impediment to the accumulation of immunity in populations. We used an agent-based mathematical model of GAS transmission to investigate the epidemiological consequences of enduring strain-specific immunity developing only after two infections with the same strain within a specified interval. Accounting for uncertainty when correlating murine timeframes to humans, we varied this maximum inter-infection interval from 3 to 420 weeks to assess its impact on prevalence and strain diversity, and considered additional scenarios where no maximum inter-infection interval was specified. Model outputs were compared with longitudinal GAS surveillance observations from northern Australia, a region with endemic infection. We also assessed the likely impact of a targeted strain-specific multivalent vaccine in this context. Our model produced patterns of transmission consistent with observations when the maximum inter-infection interval for developing enduring immunity was 19 weeks. Our vaccine analysis suggests that the leading multivalent GAS vaccine may have limited impact on the prevalence of GAS in populations in northern Australia if strain-specific immunity requires repeated episodes of infection. Our results suggest that observed GAS epidemiology from disease endemic settings is consistent with enduring strain-specific immunity being dependent on repeated infections with the same strain, and provide additional motivation for relevant human studies to confirm the human immune response to GAS skin infection.
Bioengineering horizon scan 2020
(ELIFE SCIENCES PUBLICATIONS LTD, 2020-05-29)
Horizon scanning is intended to identify the opportunities and threats associated with technological, regulatory and social change. In 2017 some of the present authors conducted a horizon scan for bioengineering (Wintle et al., 2017). Here we report the results of a new horizon scan that is based on inputs from a larger and more international group of 38 participants. The final list of 20 issues includes topics spanning from the political (the regulation of genomic data, increased philanthropic funding and malicious uses of neurochemicals) to the environmental (crops for changing climates and agricultural gene drives). The early identification of such issues is relevant to researchers, policy-makers and the wider public.
The significance and expectations of HIV cure research among people living with HIV in Australia
(PUBLIC LIBRARY SCIENCE, 2020-03-04)
Most people living with HIV (PLHIV) with reliable access to antiretroviral treatment (ART) have a life expectancy similar to uninfected populations. Despite this, HIV can negatively affect their social and psychological wellbeing. This study aimed to enhance understanding of the expectations PLHIV hold for HIV cure research and the implications this has for HIV cure research trials. We interviewed 20 Australian PLHIV about their expectations for HIV cure research outcomes and the impact a potential cure for HIV may have on their everyday lives. Data were analysed thematically, using both inductive and deductive approaches. The significance of a cure for HIV was expressed by participants as something that would offer relief from their sense of vigilance or uncertainty about their health into the future. A cure was also defined in social terms, as alleviation from worry about potential for onward HIV transmission, concerns for friends and family, and the negative impact of HIV-related stigma. Participants did not consider sustained medication-free viral suppression (or remission) as a cure for HIV because this did not offer certainty in remaining virus free in a way that would alleviate these fears and concerns. A cure was seen as complete elimination of HIV from the body. There is an ethical need to consider the expectations of PLHIV in design of, and recruitment for, HIV cure-related research. The language used to describe HIV cure research should differentiate the long-term aspiration of achieving complete elimination of HIV from the body and possible shorter-term therapeutic advances, such as achieving medication free viral suppression.
Manual of Travel Medicine Fourth Edition
(Springer Singapore, 2019)
The fourth edition of this well received book provides an authoritative and up-to-date resource to support good practice in travel medicine, a field that has evolved substantially in recent years. Concretely, there has been intensified monitoring of health problems among travelers, as well as extensive research efforts, which have led to the development of evidence-based approaches to the field. The book includes expert recommendations regarding e.g. immunizations, malaria prophylaxis, travelers’ diarrhea, altitude sickness, emerging infections, and non-infectious health issues encountered by travelers. It provides a practical approach to the pre-travel consultation and management of most issues that arise in medical care for travelers. In addition, it provides expert advice for high-risk travelers, e.g. those with immunosuppression, the elderly, pregnant women and young children. The text offers a user-friendly, practical handbook for healthcare practitioners during their clinical consultations, as well as nurses and pharmacists.
Sex and sport: sexual risk behaviour in young people in rural and regional Victoria
(CSIRO PUBLISHING, 2010-01-01)
BACKGROUND: To determine the prevalence of chlamydia and understand sexual risk behaviour in 16-29 year olds in rural Victoria through a chlamydia testing program undertaken at local sporting clubs. METHODS: Young people were recruited from the Loddon Mallee region of Victoria, Australia between May and September 2007. After a night of sporting practice, participants provided a first pass urine sample and completed a brief questionnaire about sexual risk behaviour. Those positive for chlamydia were managed by telephone consultation with a practitioner from Melbourne Sexual Health Centre. RESULTS: A total of 709 young people participated (77% male, 23% female) in the study; 77% were sexually active. Overall chlamydia prevalence in sexually active participants was 5.1% (95% confidence interval [CI]: 3.4-7.3); 7.4% in females (95% CI: 3.5-13.6) and 4.5% in males (95% CI: 2.7-6.9). Approximately 60% of males and 20% of females consumed alcohol at high 'Risky Single Occasion Drinking' levels at least weekly and 60% had used an illicit drug in their lifetime. Nearly 45% reported having sex in the past year when they usually would not have because they were too drunk or high. Sexually transmissible infection (STI) knowledge was generally poor and only 25% used a condom the last time they had sex. CONCLUSION: Chlamydia prevalence was high in our study population. Many participants had poor knowledge about STIs and low condom use. These findings combined with high levels of risky alcohol use and having sex while intoxicated highlights the need for programs in rural and regional Victoria that combine both STI testing and prevention and education programs.
Australian general practitioner chlamydia testing rates among young people
(AUSTRALASIAN MED PUBL CO LTD, 2011-03-07)
OBJECTIVE: To describe the proportion of 16-29-year-olds tested for chlamydia by Australian general practitioners in a 12-month period. DESIGN AND SETTING: Between October 2007 and September 2008, the national chlamydia testing rate in 16-29-year-olds was calculated by dividing the number of Medicare-reimbursed chlamydia tests by two denominators: (i) Medicare-reimbursed GP consultations; and (ii) estimated resident populations adjusted for the proportion who were sexually active. MAIN OUTCOME MEASURES: GP chlamydia testing rates in 16-29-year-olds per 100 patients attending a GP consultation and per 100 sexually active population, by patient age and sex, state/territory of residence, and remoteness area. RESULTS: Among the estimated Australian population of 16-29-year-olds, 85.6% of females and 64.4% of males had at least one GP consultation in the 12-month period. The national GP chlamydia testing rate per 100 patients was 8.9% (95% CI, 8.88%-8.94%). The national GP chlamydia testing rate per 100 sexually active population was 8.0% (95% CI, 7.92%-7.98%). The rate per 100 sexually active population was higher in females (12.5%) compared with males (3.7%) (P < 0.01); higher in 20-24-year-olds (9.0%) compared with 16-19-year-olds (8.7%) and 25-29-year-olds (6.6%) (P < 0.01); higher in those living in non-metropolitan areas (11.0%) compared with metropolitan areas (8.4%) (P < 0.01); and highest in those living in the Northern Territory (21.4%) compared with other jurisdictions (P < 0.01). CONCLUSIONS: Despite clinical guidelines recommending annual chlamydia testing for sexually active 15-29-year-olds, our analysis showed that a high proportion of young people aged 16-29 years attend a GP each year, but few of the sexually active population in this age group were tested for chlamydia in general practice. Strategies are needed to support GPs to enhance chlamydia testing in young people.
Missed opportunities-low levels of chlamydia retesting at Australian general practices, 2008-2009
(BMJ PUBLISHING GROUP, 2012-08-01)
OBJECTIVE: Chlamydia reinfection is common and increases the risk of reproductive complications. Guidelines for Australian general practitioners recommend retesting 3-12 months after a positive result but not before 6 weeks. The authors describe retesting rates among 16-29-year-old patients diagnosed as having chlamydia at 25 general practice clinics participating in the Australian Collaboration for Chlamydia Enhanced Sentinel Surveillance system. METHODS: The authors calculated annual testing and positivity rates for 16-29-year-olds attending in 2008-2009, re-attendance and retesting rates within <6 weeks, 1.5-4 months and 1.5-12 months of a positive test in 2008-2009 and positivity at retest (where results were available). Results There were 50,408 individuals (60.4% women) who attended in 2008-2009. Annually, 7.4% and 7.3% were tested for chlamydia, of whom 9.1% and 8.0% tested positive, respectively. Within 1.5-4 months of a positive test, 24.6% re-attended and were retested (19% tested positive), 31.6% re-attended and were not retested and 43.9% did not re-attend. Within 1.5-12 months, 40% re-attended and were retested (16% tested positive), 40% re-attended and were not retested and 20% did not re-attend. Of individuals re-attending in 1.5-12 months but not retested, 50% had re-attended three or more times in the period. Within 6 weeks of a positive test, 25% were retested. DISCUSSION: A high proportion of 16-29-year-olds re-attended general practices in the recommended retest periods, but retesting rates were low and multiple missed opportunities were common. The findings highlight the need for strategies such as electronic clinician prompts, patient recall systems and promotion of retesting guidelines.
Self-reported cognitive function in a large international cohort of people with multiple sclerosis: associations with lifestyle and other factors
BACKGROUND AND PURPOSE: We aimed to estimate the prevalence of perceived cognitive impairment (PCI) and explore its associations with lifestyle and disease characteristics in a large international cohort of people with multiple sclerosis (MS). METHODS: This study was a cross-sectional analysis. Participants rated their cognitive function over the preceding 4 weeks using four questions in a subscale within the Multiple Sclerosis Quality of Life questionnaire (MSQOL-54). These questions assessed perceived concentration, attention and memory by the patient and family/friends. Four definitions of PCI were derived, ranging from lowest to highest specificity. Associations with PCI were assessed by log-binomial regression. RESULTS: The prevalence of PCI in our sample ranged from 41.0% (95% confidence interval, 39.0-43.0) using the least-specific definition to 11.6% (95% confidence interval, 10.3-12.9) using the most specific definition. A number of factors were associated with PCI, increasing in magnitude as the definition specificity increased, including positive associations for smoking and body mass index, whereas physical activity, dietary quality and use of vitamin D/omega-3 supplements were inversely associated with PCI. CONCLUSIONS: Our study reports associations between healthy lifestyle behaviours and PCI in people with MS. Although reverse causality is a potential explanation for our findings, previous studies have shown comparable associations with healthy lifestyle and MS onset and progression. Subject to external validation, these results suggest benefits realized from a healthy lifestyle in people with MS.
Prevalence of Hepatitis C Among Australian Aboriginal and Torres Strait Islander people: A Systematic Review and Meta-Analysis
(KOWSAR PUBL, 2016-07-01)
CONTEXT: Aboriginal and Torres Strait Islanders (Aboriginal) account for approximately 3% of the Australian population. They have the poorest health, economic and social outcomes. Higher notification rates of hepatitis C antibodies (anti-HCV) have been reported among Aboriginal compared with non-Aboriginal people. The identification of Aboriginal people in national surveillance has some weaknesses, with only four of the eight jurisdictions included in national reporting. To address some of these limitations, we aim to estimate the pooled prevalence of anti-HCV among Aboriginal people in Australia. EVIDENCE ACQUISITION: We searched the databases: Pubmed, Web of Science and Informit, and the New South Wales and Northern Territory Public Health Bulletins. A study was included if it reported the number of Aboriginal people testing positive for anti-HCV and the number tested for anti-HCV. A meta-analysis by population-group was conducted if three or more studies reported a prevalence estimate. Variables included: author, year of publication, study design, study period, gender (female, male), age, population group (Aboriginal people in prison, Aboriginal people who inject drugs), number testing anti-HCV positive, number tested for anti-HCV and prevalence (%). Due to a long time period, we separated the studies estimating the prevalence anti-HCV among Aboriginal people in prison into two time periods, 1994 - 2004 and 2005 - 2012. RESULTS: Overall, 15 studies met our inclusion criteria. Among Aboriginal people in prison, the pooled prevalence of anti-HCV was 18.1% (95%CI: 6.6 - 29.7). The pooled prevalence among Aboriginal people in prison was 25.7% (95%CI: 4.1-47.3) in studies published between 1994 - 2004 and 14.5% (95%CI: 1.7 - 27.3) in studies published from 2005 - 2012. The pooled prevalence of anti-HCV was 58.7% (95%CI: 53.9 - 63.5) among Aboriginal people who inject drugs and 2.9% (95%CI: 0.30 - 6.1) among Aboriginal people who did not inject drugs, however there was significant heterogeneity (I(2) > 90.0%, P < 0.01). There was significant selection bias in the studies as most included individuals who inject drugs. CONCLUSIONS: Our analysis shows that the overall prevalence of anti-HCV was significantly biased towards people who inject drugs; resulting in an over-estimation of anti-HCV prevalence among Aboriginal people. Our review highlights that unsafe injecting is the main transmission route for HCV infection among Aboriginal people in Australia.
A new national Chlamydia Sentinel Surveillance System in Australia: evaluation of the first stage of implementation.
The Australian Collaboration for Chlamydia Enhanced Sentinel Surveillance (ACCESS) was established with funding from the Department of Health and Ageing to trial the monitoring of the uptake and outcome of chlamydia testing in Australia. ACCESS involved 6 separate networks; 5 clinical networks involving sexual health services, family planning clinics, general practices, antenatal clinics, Aboriginal community controlled health services, and 1 laboratory network. The program ran from May 2007 to September 2010. An evaluation of ACCESS was undertaken in early 2010, 2 years after the program was funded. At the time of the evaluation, 76 of the 91 participating sites were contributing data. The jurisdictional distribution of the 76 sites generally matched the jurisdictional distribution of the Australian population. In 2008, the chlamydia testing rates in persons aged 16-29 years attending the 26 general practices was 4.2% in males and 7.0% in females. At the 25 sexual health services, the chlamydia testing rates in heterosexuals aged less than 25 years in 2008 was 77% in males and 74% in females. Between 2004 and 2008, the chlamydia positivity rate increased significantly in heterosexual females aged less than 25 years attending the sexual health services, from 11.5% to 14.1% (P < 0.01). Data completeness was above 85% for all core variables except Aboriginal and/or Torres Strait Islander status and country of birth, which ranged from 68%-100%, and 74%-100%, respectively, per network. There were delays in establishment of the system due to recruitment of 91 sites, multiple ethics applications and establishment of automated extraction programs in 10 different database systems, to transform clinic records into a common, pre-defined surveillance format. ACCESS has considerable potential as a mechanism toward supporting a better understanding of long-term trends in chlamydia notifications and to support policy and program delivery.
Sex and sport: chlamydia screening in rural sporting clubs
(BIOMED CENTRAL LTD, 2009-05-27)
BACKGROUND: Chlamydia trachomatis is the most common notifiable disease in Australia, mainly affecting those aged 15 to 29 years. Testing rates are low in Australia and considerably lower in rural areas, with access and confidentiality of sexual health services being problematic in rural and regional areas. This study aimed to determine the feasibility of establishing a pilot chlamydia testing outreach program among 16-25 year old males and females in rural Victoria (Australia) undertaken at local sporting clubs and to determine the prevalence of chlamydia and acceptability of the program in this population. METHODS: We aimed to recruit young people from the Loddon Mallee region of Victoria, Australia between May and September 2007. After a night of sporting practice, participants provided a first pass urine sample, completed a brief questionnaire regarding risk taking behaviour and were then provided with condoms and health promotion materials about sexually transmitted infections (STIs). Those positive for chlamydia were managed by telephone consultation with a practitioner from Melbourne Sexual Health Centre. RESULTS: A total of 709 young people participated (77% male, 23% female), 77% being sexually active. All provided a urine sample and completed the questionnaire. Participation rate on recruitment nights was over 95%. Overall chlamydia prevalence in those sexually active was 5.1% (95%CI: 3.4-7.3), 7.4% in females (95%CI: 3.5-13.6) and 4.5% in males (95%CI: 2.7-6.9). CONCLUSION: Sporting clubs represent a feasible, acceptable and innovative community based setting to screen, treat and educate young people in a rural and regional setting, especially for males.
A systematic examination of the use of Online social networking sites for sexual health promotion
BACKGROUND: In recent years social networking sites (SNSs) have grown rapidly in popularity. The popularity of these sites, along with their interactive functions, offer a novel environment in which to deliver health promotion messages. The aim of this paper is to examine the extent to which SNSs are currently being used for sexual health promotion and describe the breadth of these activities. METHODS: We conducted a systematic search of published scientific literature, electronic sources (general and scientific search engines, blogs) and SNSs (Facebook, MySpace) to identify existing sexual health promotion activities using SNSs. Health promotion activities were eligible for inclusion if they related to sexual health or behaviour, utilised one or more SNSs, and involved some element of health promotion. Information regarding the source and type of health promotion activity, target population and site activity were extracted. RESULTS: 178 sexual health promotion activities met the inclusion criteria and were included in the review; only one activity was identified through a traditional systematic search of the published scientific literature. Activities most commonly used one SNS, were conducted by not-for-profit organisations, targeted young people and involved information delivery. Facebook was the most commonly used SNS (used by 71% of all health promotion activities identified), followed by MySpace and Twitter. Seventy nine percent of activities on MySpace were considered inactive as there had been no online posts within the past month, compared to 22% of activities using Facebook and 14% of activities using Twitter. The number of end-users and posts in the last seven days varied greatly between health promotion activities. CONCLUSIONS: SNSs are being used for sexual health promotion, although the extent to which they are utilised varies greatly, and the vast majority of activities are unreported in the scientific literature. Future studies should examine the key factors for success among those activities attracting a large and active user base, and how success might be measured, in order to guide the development of future health promotion activities in this emerging setting.