Projects

Individual-based models of tuberculosis control in Vietnam

This PhD project is looking at the effects of screening strategies on Tuberculosis incidence and mortality in Vietnam, using detailed outcomes data from a recent RCT.

Changing measles epidemiology in Australia and appropriate responses

This project uses models to examine the impacts of Australia’s changing immune profile to measles and seeks to harmonise predictions based on serological and notification-based data in Australia. This project encompasses a number of areas, including improved models of measles immune responses, statistical approaches for analysing outbreak data, analysis of how local variation in vaccine…

Examining impacts of demographic change on herpes zoster incidence in Australia

This project uses models that account for changing demographics (in particular birth and death rates) to examine changes in herpes zoster incidence prior to vaccination. This builds on the work of David Earn in respect to measles in New York City and more recent models applied in Italy and Spain suggesting that such effects can…

Assessing impacts of acellular vaccines on circulating pertussis strains

This project is using stochastic models of pertussis dynamics including strain diversity to examine whether acellular vaccination has been driving evolutionary changes. Moreover the aim is to examine the public importance of such changes and whether this  requires a rethink on our approach to vaccination for pertussis.

The influence of social connectedness on health

Social connectedness has been associated with reduced morbidity and mortality in a range of studies over recent decades. In response, agencies involved in health promotion at local government and State level have prioritised improving neighbourhood connectedness. This study will develop data-driven computational network models to characterise connectedness between households in selected geographical areas of metropolitan Melbourne, with contrasting demographic,…

Assessing medium-to-long term vaccine impact in household-structured populations undergoing demographic change

The household has long been recognised as a key focus of infection transmission. Hope-Simpson described a four-fold risk of ‘Hong Kong’ influenza, the 1968 pandemic strain, among family members of an affected case. More recent observations of seasonal and pandemic influenza spread have confirmed these risks, which are particularly pronounced when children are primary cases or contacts. Family…

Emerging drug resistant pathogens in healthcare settings

Drug resistant bacteria are an emerging infectious disease threat of the 21st century, with some people claiming that we are approaching the post-antibiotic era. Hospital acquired infections seem to lead community acquired infections in developing resistance. This is likely due to a combination of forces, such as the over-use of antibiotics in hospitals, the proximity…

Tuberculosis

Tuberculosis is a major infectious diseases killer globally with 1.8 million deaths estimated in 2014.The Asia-Pacific region makes up most of the burden of TB, has several hotspots of very high incidence of tuberculosis, and rising drug resistance making it a major focus in the battle for TB elimination. Modelling of both transmission dynamics and…

Hepatitis C and the role of injecting networks

For many infectious diseases, contact patterns that lead to spread of the disease are far from random. They are defined by complex social interactions which can be difficult to measure. Particularly for blood borne viruses such as Hepatitis C, contracted predominantly through injecting drug use, contacts capable of transmitting disease are well defined. It is…

Understanding the epidemiology of Respiratory Syncytial Virus (RSV)

Respiratory Syncytial Virus (RSV) is the most common cause of respiratory infections in infants and young children. While RSV presents a significant health and economic burden both in Australia and internationally, its epidemiology is currently not well understood. We collaborate with Dr Hannah Moore from the Telethon Institute in Western Australia to fit mathematical models…

Severity, vaccination, and interference between influenza and other respiratory infections

Influenza is an ongoing issue in Australia leading to significant morbidity and mortality, particularly in the elderly. Disease severity and vaccination are crucial in understanding the spread and burden of influenza, while many other viral pathogens also contribute to the burden of respiratory disease. There is emerging evidence that exposure to one infection may provide…

Understanding the sub-optimal response to ivermectin and implications for onchocerciassis control

Onchocerciasis, or African river blindness, has been subject to extensive public health interventions designed to reduce the burden of disease over the past two decades. Spraying programs for vector control followed by ivermectin treatment for affected communities (mass drug administration) have been successful in dramatically reducing the public health burden of the disease. These initiatives…

Antimalarial drug resistance

In 2013 there were an estimated 198 million clinical cases of malaria and 584,000 deaths from malaria worldwide. Nearly all deaths and most serious morbidity are due to the parasite Plasmodium falciparum. The World Health Organization currently recommends an artemisinin derivative combined with another antimalarial drug as the first line treatment of falciparum malaria. At…

The dynamical properties of transmission models

Endemic infectious diseases constantly circulate in human populations, with prevalence fluctuating about a (theoretical and unobserved) time-independent equilibrium. For diseases for which acquired immunity is not lifelong, the classic susceptible–infectious–recovered–susceptible (SIRS) model provides a framework within which to consider temporal trends in the observed epidemiology. However, in some cases (notably pertussis), sustained multiannual fluctuations are…

Spatio-temporal modelling of seasonal influenza

Temperate climates regularly witness a seasonal influenza epidemic. However there is considerable variation in the timing and severity of these epidemics. Availability of accurate forecasts would allow epidemiologists to develop appropriate responses ahead of time, potentially saving lives and reducing the burden placed on the health system. Moreover, the ability to forecast from a model…

The host response to influenza

Despite extensive study, the role of different components of the immune response in resolving influenza virus infection remains quantitatively unclear. In collaboration with colleagues at the WHO Collaborating Centre for Reference and Research on Influezna at the Peter Doherty Institute, we have applied consecutive exposures to different virus strains in a ferret model, and demonstrated…

Hybrid Markov chain models for disease dynamics

From the early work of Daniel Bernoulli to the recent outbreak of Ebola, the mathematical modelling of infectious diseases is of fundamental importance to quantifying the threats that diseases pose to society. These models often strive to achieve either a high degree of accuracy or to be easily amenable to analysis by practitioners. Continuous-time Markov…

Assimilating digital social data into epidemiological forecast models

Accurate forecasting of disease outbreaks relies on understanding complex human dynamics—our mobility, social interactions and behaviour in response to factors like emergencies and mass media. While many studies have attempted to incorporate so-called “media effects” into dynamical transmission models, these models have necessarily not been highly data-driven. However, the recent “big data” explosion coming from…

Optimal experimental design for group dose-response challenge experiments

Optimising the design of experiments is an important consideration in many areas of science (e.g. in biology, chemical engineering, clinical trials, and epidemiology). The theory of optimal experimental design is a statistical tool that allows us to determine the optimal experimental protocol to gain the most information about model parameters, subject to constraints on available…

Clostridium difficile: assessing the risks to Australia of an emerging healthcare-related pathogen.

This study investigates the ribotype profile of C. difficile organisms infecting a broad spectrum of hospital patients (both symptomatically and asymptomatically) and community members in Queensland and Western Australia, and associated clinical outcomes. Mathematical models are being developed to investigate the impact of C. difficile interventions, and interactions between hospitals and the community. This research…

Optimising pertussis vaccination strategies

Pertussis remains challenging to control, despite widespread use of vaccines to protect infants and children from this disease over many decades. Resurgence of disease has been evidenced by an increase in infant deaths in the US and UK in recent years, and by a rise in notifications and hospitalisations in Australia. We have used models of pertussis infection to consider…

Inference for epidemics on networks

One of the most basic models we have for describing the spread of a disease is the SIR model. The SIR model splits a population into three groups: (S)usceptible, (I)infected and (R)ecovered. One question we might want to ask is, given we know how many people were infected over the course of an epidemic what is an estimate of…

Calculating the probability of epidemic fade-out

An epidemic may exhibit a “boom then bust” on its initial outbreak. The number of infected individuals reaches a high first peak, and then falls to a low first trough as individuals recover and become immune. During this first trough the infection may fade out completely (“epidemic fade-out”), or rise again to an endemic level…