Contact details

Professor Christophe Fraser

Professor of Theoretical Epidemiology
Division of Epidemiology, Public Health and Primary Care

G28
Norfolk Place
St Mary's Campus

Email:

Professor Christophe Fraser

Infectious disease dynamics

I work on the theory of infectious disease dynamics, and also develop applied models for use in the public health arena. Infectious disease dynamics takes a unified view of the epidemiology and evolution of pathogens, driven by complex underlying patterns of host-host, host-pathogen and pathogen-pathogen interactions which require careful disentangling.

I study these systems using a spectrum of tools ranging from simple mathematical models to complex computer simulations, never in isolation, but always interacting with microbiologists, basic medical scientists and public health professionals.

I am a Royal Society University Research Fellow.

HIV infection dynamics

I am interested in aspects of within and between host dynamics, control and evolution of HIV.

Our attention has been shifting from within-host replication dynamics, HIV recombination and drug resistance, to issues surrounding the epidemic spread of infection. One important theme is characterising heterogeneities in people's transmissibility. We have been particularly focussing on the role of heterogeneity in viral load.

We have recently proposed the hypothesis that HIV may have adapted to maximise it's transmissibility between hosts, and are currently testing this with data collected by our collaborators in the Netherlands, and from the Rakai cohort.

• Fraser C; Hollingsworth TD; Chapman R; de Wolf F; Hanage WP. (30 Oct 2007). Variation in HIV-1 set-point viral load: epidemiological analysis and an evolutionary hypothesis. Proc Natl Acad Sci U S A. 104:17441-17446. Publisher weblink DOI.

Outbreak analysis and modelling

One message I took away from my involvement in analysing the 2003 Hong Kong SARS outbreak, principally with Steven Riley, is that surveillance can and should allow analysis of epidemics in real time.

My focus on developing analytical mathematical techniques that make efficient use of these data. I have been concentrating on influenza pandemic modelling, where simple analytical techniques provide very complementary insights to individual based microsimulations developed by Neil Ferguson.

SARS control was characterised by the successful use of old fashioned public health: hygiene, isolation, contact tracing, school and workplace closures, etc... aided by the very modern techniques for the dispersal of vital and accurate information.

What determines the likely sucess or failure of such measures? One factor that was clearly important for SARS was the early appearance of symptoms relative to infectiouness. We examined the importance of this and other factors in a recent study (see Figure and link below). Will we be so lucky next time?

• Fraser C. (2007). Estimating individual and household reproduction numbers in an emerging epidemic. PLoS ONE. 2:e758-e758. Publisher weblink DOI.
• Fraser C; Riley S; Anderson RM; Ferguson NM. (20 Apr 2004). Factors that make an infectious disease outbreak controllable. Proc Natl Acad Sci U S A. 101:6146-6151. Publisher weblink DOI.
• Wu JT; Riley S; Fraser C; Leung GM. (Sep 2006). Reducing the impact of the next influenza pandemic using household-based public health interventions. PLoS Med. 3:e361-e361. Publisher weblink DOI.
• Ferguson NM; Cummings DA; Fraser C; Cajka JC; Cooley PC; Burke DS. (27 Jul 2006). Strategies for mitigating an influenza pandemic. Nature. 442:448-452. Publisher weblinkDOI.

Evolution and epidemiology of common bacterial pathogens

Understanding the population genetics of bacterial species, identifying the mechanisms and factors which have created the visible patterns of inter-relatedness between bacteria, is critical to making sense of the way drug resistance, virulence or vaccines work. I work with Bill Hanage and Brian Spratt who sequence DNA from many bacteria. We then develop mathematical models to explain the patterns they see.

We have developed new models which explain the observed diversity of bacterial genotypes within samples of carried bacteria. We have more recently been interested in how patterns of horizontal gene flow between related groups of bacteria relate to population structure and the formation of new bacterial species.

• Fraser C; Hanage WP; Spratt BG. (26 Jan 2007). Recombination and the nature of bacterial speciation. Science. 315:476-480. Publisher weblink DOI.
• Fraser C; Hanage WP; Spratt BG. (08 Feb 2005). Neutral microepidemic evolution of bacterial pathogens. Proc Natl Acad Sci U S A. 102:1968-1973. Publisher weblink DOI.

Epidemiological theory

Together with Nick Grassly, we have been reviewing and extending methods to infer biological drivers of endemic and seasonal infection dynamics. This work has found applications in the studying the dynamics of syphillis and gonorrhea in the USA, and polio in India.

• Grassly NC; Fraser C; Wenger J; Deshpande JM; Sutter RW; Heymann DL; Aylward RB. (17 Nov 2006). New strategies for the elimination of polio from India. Science. 314:1150-1153. Publisher weblink DOI.
• Grassly NC; Fraser C; Garnett GP. (27 Jan 2005). Host immunity and synchronized epidemics of syphilis across the United States. Nature. 433:417-421. Publisher weblinkDOI.

with Hugo (7) and Iselin (5)

Other activities

I direct a two week short course held each September, that offers an introduction to quantitative infectious disease epidemiology for public health professionals. I also teach on, and help organise, our MSc in Modern Epidemiology.

I am the deputy director of the new MRC centre for outbreak analysis and modelling.

Recent Press Releases

• Shortlisted for "Lancet Paper of the Year" (2008) PDF
• HIV is spread most by people with medium levels of HIV in blood, says study" (2007)