Research > Research Strength: Infectious Diseases
Research Strength: Infectious Diseases
Infectious diseases research at the School of Public Health and Community Medicine
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Introduction
At UNSW SPHCM, we have a large critical mass of multidisciplinary expertise in epidemiology, mathematical modelling, health economic modelling, special risk populations, social research and clinical research in infectious diseases. Few groups have the necessary training to bridge these diverse areas and bring them together in truly multidisciplinary research. For example, our clinical trials have within them sub-studies that involve mathematical modelling and health economic evaluation. This allows the maximum value to be gained from our research. The multidisciplinary nature of our research also facilitates the translation of research outcomes into policy and practice.
Epidemiology
Hospital infection control and epidemiology
– A/Prof Mary Louise McLaws
The epidemiology and control of healthcare associated infections lacked a standardised valid approach and the work undertaken in this area has included: the development of a standardised surveillance protocol for hospitals that enabled hospitals to target surveillance techniques of their core patient group and introduced hospital-based standardised analysis that enabled establishing benchmarking from valid aggregated data for sentinel infections. As hospitals are undertaking standardised surveillance and analysis the next step was establishing a valid post-discharge surveillance method for early discharge, especially targeting surgical site infections. Research into other patient safety and behavioural issues that are researched included analysis of an improved technique for the insertion of central venous lines to reduce bacteraemia and mechanical adverse events, a mathematical model to understand and predict the hand hygiene behaviour of healthcare workers, modelling of healthcare workers’ engagement in reporting adverse events associated with clinical care to improve intervention of unsafe clinical care, and the epidemiology and intervention of needlestick injury.
Influenza and emerging infections
– Prof Raina Maclntyre, A/Prof Mary Louise McLaws, Dr Holly Seale, Dr James Wood, Dr Tony Newall
Case control study of influenza in patients with ischemic heart disease and stroke
There is abundant indirect epidemiologic evidence that influenza contributes to all-cause mortality and to cardiac, stroke and respiratory hospitalisations. Studies show that rates of acute myocardial infarction (AMI) and death increase during the influenza season. Despite the compelling observational epidemiologic data and the animal data, the role of infection in ischaemic events is rarely counted in burden of disease estimates and in economic evaluations. This case-control study examines the prevalence of unrecognised (as indicated by admission diagnosis) influenza (as measured by immunofluorescence, PCR and paired serology) as an underlying factor in hospital admissions during the winter months.
To develop a tool of levels of protection required for various occupational settings in a pandemic.
The Commonwealth has funded this project to critically evaluate the literature for evidence of the current knowledge and practices of protection of healthcare workers and the community during an influenza pandemic. A tool of levels of protection required for various occupational settings in a pandemic will be developed from this review with the objective that the Australia’s health system has a coordinated evidence-based protocols for the protection of its healthcare workers and those in pivotal functioning roles the community.
Modelling
a) Mathematical modelling studies
– Dr James Wood, Dr Zhanhai Gao, Dr Tony Newall
Measles
Australia is currently experiencing very low levels of measles cases and appears to have been successful at eliminating endemic measles transmission. We have used vaccine coverage and cross-sectional serological data to predict whether current vaccination strategies will be sufficient to maintain elimination in the near to medium term future. By using models of the immune proportion in Australia that include timing of vaccination, coverage and waning of vaccine-derived immunity we are able to study how changes in programs might affect this status.
Varicella zoster
A mathematical model of varicella zoster virus (VZV) transmission was reconstructed to examine the impact of VZV vaccination on the epidemiology of VZV in Australia using lower vaccine effectiveness (VE) estimates and incorporating higher levels of waning immunity. New matrix of WAIFW (Who-Acquired-Infection-From-Whom) was built using Australian serosurvey results. VE parameters were estimated using the data of annual varicella event rate of ten-year follow-up of health children who received one injection of varicella in USA. Model was used to evaluate the impact of vaccination on varicella and zoster incidence, average age of infection and VZV morbidity (inpatient days) in Australia.
Pandemic influenza
Currently we are using models to examine population protection with limited vaccine stockpiles, and the related question of whether targeted or population based strategies are preferable for pre-pandemic vaccines. The first topic involves the interesting question of whether it is better to reduce the antigen content (and thus individual protection) per vaccine in order to get greater population coverage so that herd immunity effects come into play. This issue of the timing of vaccination programs is also crucial in this context and can lead to situations where one-dose programs with less immunogenic vaccines are superior to two-dose programs.
The second topic is linked with cost-effectiveness analyses and considers the effect of targeted or whole of population pre-pandemic vaccine programs on attack rates in a more structured population. Evidence of good cross-protection by candidate vaccines indicates that this could be effective as supplement or even replacement of antiviral based control strategies.
Prior work has included simple patch-based stochastic models investigating the effect of travel restrictions (
http://www.cdc.gov/EID/content/13/7/pdfs/1038.pdf) on within country transmission.
b) Health economic studies
– Dr Tony Newall, Dr James Wood, Prof Raina MacIntyre
The economic evaluation of infectious diseases offers a unique set of challenges. The recent work of our group has focused on the prevention of seasonal influenza, pandemic influenza, and rotavirus.
Influenza
The Australian Government funds universal influenza vaccine for all those aged ≥65 years. We have completed an economic evaluation of universal influenza vaccination for Australians aged 50-64 years. This analysis used a decision analytic model to examine the cost-effectiveness of lowering the age threshold for the universal vaccination program.
The economic analysis was informed by a burden of illness study estimating the influenza-attributable disease burden in Australians aged over 50 years. Statistical regression techniques, using laboratory surveillance data, were used to determine the excess number of deaths and hospitalisations caused by influenza.
Rotavirus
We recently completed an economic evaluation of infant rotavirus vaccination. This analysis used a Markov model to evaluate the cost-effectiveness of universal rotavirus vaccination in Australia. Since the completion of this research, a universal rotavirus vaccination program for all Australian infants has been funded.
Pandemic influenza
The nature and timing of a future influenza pandemic is inherently uncertain. This creates difficulties when determining the appropriate resource allocation for pandemic planning against other government spending. We are currently using mathematical models to evaluate the cost-effectiveness of pharmaceutical-based strategies for the prevention/mitigation of pandemic influenza.
Clinical Research
This including individual and cluster randomised, controlled trials of drugs, vaccines and non-pharmaceutical interventions
– Prof Raina Maclntyre, A/Prof Mary Louise McLaws, Dr Holly Seale
RCT of pneumococcal conjugate vaccine vs. polysaccharide vaccine in hospitalised elderly (NHMRC)
Prof Raina MacIntyre, Prof Richard Lindley, Dr Iman Ridda, Prof Lyn Gilbert, A/Prof John Sullivan, Prof Peter McIntyre. This trial compares the immunogenicity of conjugate and polysaccharide pneumococcal vaccines in hospitalised elderly. Recruitment is complete and final laboratory testing is underway.
Clinical trial of pneumococcal conjugate vaccine in bone marrow transplant patients (NHMRC CCRE)
Prof Raina MacIntyre, Dr Nicole Gilroy, Prof Ken Bradstock, Prof Tania Sorrell, Prof Lyn Gilbert, Prof Peter McIntyre, Ms Masrura Kabir, Ms Claire Kesby.
This trial looks at different schedules of pneumococcal conjugate vaccine in adult BMT patients. Recruitment is complete and final laboratory testing is underway.
Clinical trial of quadrivalent HPV vaccine in immunosuppressed children (NHMRC CCRE)
Prof Raina MacIntyre, A/Prof Peter Shaw, Dr Ted O’Loughlin, Dr Michael Stormon, Dr Fiona Mackie, Ms Kay Montgomery et al. This trial is about immunogenicity and duration of immunity in immunosuppressed children aged 5 to 15 years with BMT or solid organ transplants to HPV vaccine.
RCT of face masks in prevention of respiratory viral infection (Department of Health and Ageing funded trial)
In planning for a pandemic or emerging infection, a randomised controlled trial to determine efficacy of facemasks in preventing transmission of respiratory pathogens has been identified as a high priority by governments around the world. Whilst there has been high investment in research around the use of vaccines and pharmaceuticals, shortages of antivirals and delay in production of vaccines make non-pharmaceutical interventions critical in the early phases of a pandemic. Whilst in principle the use of masks is probably protective, the difference between the readily available ordinary surgical masks and the more expensive particulate respirators such as P2 or N95 masks are unknown. Therefore, this study aims to determine the impact of the use of surgical masks and P2 particulate respirators in households on the interruption of transmission of influenza and other respiratory viruses.
RCT of face masks in hospital health care workers in Asia. (UNSW)
The established zooendemicity of H5N1 avian influenza A H5N1 globally is a serious threat to human health because of the risk of emergence of a human pandemic strain. For pandemic influenza or other emerging infections such as SARS, it is likely that antivirals will be unavailable or in short, supply and that vaccine production will be delayed, as a matched vaccine can take 3 to 6 months to be developed and produced. This makes the role of non-pharmaceutical interventions such as infection control (including hand washing, use of masks etc) crucial as an early disease control strategy. However, there are major gaps in knowledge about the impact of non-medical interventions on the transmission of influenza and other respiratory viruses. Despite the lack of high-level evidence, recommendations on the use of facemasks for health care workers are made by authorities in many countries. The aim of this study is to determine the impact of surgical masks and P2 particulate respirators on the interruption of transmission of influenza and other respiratory viruses in hospital health care workers. The study is being assessed for feasibility currently.
Social and Behavioural Research
– Prof Nick Zwar, A/Prof Juliet Richters, Dr Niamh Stephenson, Dr Lorraine Yap
Sexual Health and Attitudes of Australian Prisoners
This NHMRC-funded study combines quantitative and qualitative research to study the sexual behaviour, health and attitudes of prisoners, a vulnerable and disadvantaged group of people who are often omitted from representative sample surveys even when they are not in prison. It aims to learn more about the patterns of sexual contact within gaols and the physical and institutional structures and practices that influence sexual health and prevent or enable sexual coercion. In the quantitative component about 2000 men and 400 women were interviewed by computer-assisted telephone interview in prisons in New South Wales and Queensland in 2006–2008. The qualitative component used fieldwork in prisons and in-depth interviews with prisoners and ex-prisoners. The study will also make practical recommendations to improve prisoners’ health and help prevent sexual assaults in prison.
Chief Investigators: Associate Professor Tony Butler (National Drug Research Institute, Curtin University), Associate Professor Juliet Richters (School of Public Health and Community Medicine, UNSW) and Professor Basil Donovan (Sydney Hospital and National Centre in HIV Epidemiology and Clinical Research, UNSW). Research Associate: Dr Lorraine Yap.
Australian Longitudinal Study of Health and Relationships
The object of this study is to document the natural history of sexual and reproductive health in the Australian population. Evidence provided from this study will allow for more effective sexual health interventions and will enable us to understand the links between ‘risk events’ and health outcomes. It will answer such questions as: What is the relationship between patterns of sexual activity and subsequent sexual functioning and reproductive health including diagnosis with sexually transmissible infections? A sample of >8000 respondents was recruited by random-digit dialling for Wave 1 in 2004–05 and has been followed up every year since then with a computer-assisted telephone interview.
Chief Investigators: Professor Anthony Smith, Professor Marian Pitts and Dr Julia Shelley, Australian Research Centre in Sex, Health & Society, La Trobe University, and Assoc Prof Juliet Richters, SPHCM.
Influenza vaccination in younger patients with chronic diseases
This project was conducted in collaboration with the National Institute of Clinical Studies to examine the gap between evidence and practice in regard to influenza vaccination of peope with chronic diseases aged less than 65. There is evidence that rates of vaccination are much lower in these people than those aged over 65. Focus groups of general practitioners and practice nurses were held to explore primary health care professionals’ views about the reasons for the gap between evidence and practice and how this could be addressed. The research was published in the Australian and New Zealand Journal of Public health.
Australian newspaper coverage of pandemic influenza
The public's everyday understandings of pandemic influenza will inform their responses to pandemic preparedness strategies and policy. This project, a qualitative analysis of Australian newspaper coverage, examines how public understandings are being shaped by media reports of pandemic and avian influenzas (Niamh Stephenson).
How are preparedness efforts taking hold in the public imagination?
Taking the public health response to pandemic influenza as a case study, this project examines disparate risk management strategies employed in the work of public health. Considerable research has been undertaken on public health’s adoption of the twin strategies of biopolitics, i.e. strategies for calculating and distributing risk across a population and strategies for individualising responsibility for risk management. These biopolitical strategies justify social interventions into people’s everyday lives – e.g. the identification of unequal distribution of disease across a population opens the possibility for interventions designed to tackle social inequalities. Pandemic influenza instances how a different approach to risk management – preparedness – is coming to the fore. In place of social interventions, preparedness efforts entail the ongoing surveillance of disease and the continuous rehearsal of state and non-state agencies coordination and response. This project examines whether (and if so how) preparedness efforts are taking hold in people’s everyday lives, and what spaces they afford for discussions and interventions into social inequalities (Niamh Stephenson).
Refugee Health Research
Refugee Studies
- Dr Mohamud Sheikh
Epidemiology of infectious diseases in refugees and internally displaced persons
The potential impact of population mobility, particularly in complex humanitarian emergencies, on health care provision is quite daunting and requires stringent understanding of the trends and burden of infectious diseases in complex humanitarian situations. Globally, there are over 50 million refugees, asylum seekers and internally displaced persons. During humanitarian emergencies they often suffer hunger and food shortages and as a result their immune system is compromised thus becoming susceptible to infectious diseases. Understanding of the epidemiology of exotic clinical and non clinical infectious diseases of refugees and internally displaced persons equips the public health practitioner with rich skills for planning and management of outbreaks of infectious diseases in this cohort.
Vitamin D deficiency and relationship to infections
Studies have shown an alarming increase in the prevalence of vitamin D deficiency worldwide, particularly in migrants and refugees. The burden of vitamin D deficiency seems to be increasing, particularly in specific populations within countries such as the United Kingdom, United States, New Zealand and Australia. Rickets is still common in developing countries such as Asia, Africa and Middle Eastern countries where most of the current Australian humanitarian resettlement is focussed.
Resettlement difficulties faced by refugees include; adjustment to differences in food, dress, and lower levels of sunlight. Since rickets cases are rare in the Australian community, vitamin D deficiency is often overlooked by general practitioners attending to their health needs; no provisions exist for vitamin D in Australia’s migrant health check. Studies carried out in developed nations on the burden of vitamin D deficiency among migrants and refugees conclude that its resurgence is real and public health practitioners need to take important actions. Vitamin D plays important role in development of strong immune system, reduction of the risk of diabetes and infectious diseases, thus its role in prevention of such diseases becomes obvious. With the increase of vitamin D deficiency in refugee populations, it is imperative to understand the relationship with infectious diseases.
Access to care
Refugees and Internally Displaced Persons(IDPs)endure conditions of social disconnection, displacement, isolation, famine, war and overcrowding, and are regarded as being among the most poor and marginalised members of the Australian community. They suffer a high rate of social, physical, emotional and mental health problems, many of which are treatable or preventable. Studies suggest that resettled refugees have poor access to diagnostic and therapeutic intervention services. The need for the development of high level management guidelines and cross-cutting intervention to improve their access to healthcare services requires extensive research.
Travel Health Research
Travel Studies
- Prof Raina MacIntyre, Prof Nick Zwar, Ms Anita Heywood
Controlling the importation of diseases into Australia by understanding traveller behaviour and travel patterns
The changing nature of organisms and emergence and re-emergence of infectious diseases, plus the impact of international travel and trade means that infectious diseases pose a continuing and evolving threat to the world. All entrants to Australia have the potential to import disease. Mathematical modelling of data on travellers traversing Australia’s borders and their contact patterns with other people can be used to understand the pathways by which infectious diseases may enter and spread around Australia. The currently available social contact data required to inform these models are inadequate and outdated. Gathering new data relevant to modern society will help to determine the best methods for controlling future infectious disease threats to our society. Detailed, unique data on demography, behavioural and social patterns of people departing and entering Australia has been collected and will be used to describe travellers to and from Australia and to develop mathematical models to evaluate effective control measures for emerging infections in Australia. An additional population study of Australians to determine the number of Australians who travel internationally, as opposed to the number of travel episodes, will add to the data available for modelling. These studies will make a unique contribution to national disease control policy.
Travel health advice and immunisation and Australian travellers
Prof Nick Zwar is the Royal Australian College of General Practitioners representative on the travel health advisory group – a joint travel industry and travel medicine group which aims to promote health travel. This group has auspiced a series of telephone surveys of Australian travellers investigating their behaviour in terms of seeking pre travel health advice and immunisation for hepatitis A and hepatitis B and their risks of contracting hepatitis B during travel. This work has resulted in two publications in the Journal of Travel Medicine.