| Other groups : | Contact structures | Model selection and Bayesian inference | Vaccination issuess | Endemicity |
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Coordinator: Jacco Wallinga (RIVM, Bilthoven) jacco.wallinga@rivm.nl
The group on SARS modelling consists of Åke Svensson, Gianpaolo Scalia-Tomba, Philip O'Neill, Kari Auranen, Christophe Fraser, Pieter Trapman, Niels Becker, Denis Mollison and Jacco Wallinga. There are three issues where some progress can be made such as to help modelling and decision-making in a future outbreak of an emerging outbreak of an infectious disease: 1) asymptomatic transmission. When can one state that with a probability of, say, 0.95 the value of the reproduction number has dropped below one, and one can one state that with a probability of 0.95 the epidemic is over? 2) modelling contact tracing. For which infections will it be possible to find infecteds by contact tracing in time? It is relatively easy to write down algorithms and do a simulation study, but obtaining exact results appears very hard. 3) estimating characteristics of spread such as the logarithmic growth rate r and reproduction number R. One can proceed by fitting detailed transmission models of the infection to observations (a highly parametric approach), or by directly estimating the realised growth rates and reproduction numbers with few assumptions about the exact transmission process (a semi-parametric approach). Which approach is more efficient and more precise? Some appropriate references: M.Eichner & K.Dietz (1996) Eradiction of poliomyelitis: when can one be sure that polio virus transmission has been terminated? American Journal of Epidemiology 143:816-822 J.Müller, M. Kretzschmar & K. Dietz (2000) Contact tracing in stochastic and deterministic epidemic models. Mathematical Biosciences 164: 39-64. S. Riley et al. (2003) Transmission dynamics of the etiological agent of SARS in Hong Kong: impact of public health interventions. Science 300: 191-196. M. Lipsitch et al. (2003) Transmission dynamics and control of severe acute respiratory syndrome. Science 300: 1966-1970. We have identified some issues concerning the SARS outbreak in 2003 that are beyond our grasp: making the data on SARS outbreaks available for all research groups, and analysing the data on SARS outbreaks in hindsight. More important, we have identified Niels will try to get some grip on the issue of asymptomatic transmission, and send a manuscript about this to the other members. Christophe will try his hand on modelling contact tracing, and send a note to the others. Jacco will send a manuscript on direct estimation of reproduction numbers to the other group members.
Maintained by Denis Mollison denis@ma.hw.ac.uk
8th September 2003