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1

Vaccination programs against mumps in the United Kingdom

Greenhalgh D., Sfikas N.

Journal of Medical Informatics & Technologies

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2003

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Vol. 5

MI13--22

EN

This paper deals with minimum elimination vaccination programs for mumps in the UK. A partial differential equation compartmental model is used to describe the spread of the disease. Pre-vaccination age-structured serological data is used to estimate the force of infection in the absence of immunization. Homogeneous, proportional and symmetric mixing are considered. Using the equilibrium equations, for each mixing assumption estimates of the basic reproduction number R0 and the minimum elimination immunization proportions for single age and two age vaccination programs are presented.

2

Prediction of infectious diseases:an exception reporting system

McCabe G., Greenhalgh D., Gettinby G., Holmes E., Cowden J.

Journal of Medical Informatics & Technologies

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2003

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Vol. 5

MI67--74

EN

In this paper prediction methods are discussed in the context of developing an exception reporting system for laboratory reports. The detection of outbreaks and longer term trends is briefly addressed, before a consideration of data types and availability to be used in evaluating the prediction methods. Four general prediction methods are outlined and the selection of data to which they are applied is examined. Both real and simulated data are used to evaluate the prediction methods and a strategy for an exception reporting system is proposed.

3

Mathematical modelling of UK rubella vaccination programs

Greenhalgh D., Sfikas N.

Journal of Medical Informatics & Technologies

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2002

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Vol. 3

MI3--11

EN

In this article we discuss mathematical modelling of vaccination programs for rubella in the UK. We briefly discuss rubella before outlining the underlying mathematical model. Age-structured serological data is used to estimate the force of infection in the absence of vaccination and hence the mixing matrix. Homogeneous, proportional and symmetric mixing are considered. The estimated mixing matrix is used to evaluate the basic reproduction number R0 and minimum elimination vaccination programs using one stage and two stage vaccination strategies.

4

Modelling the spread of AIDS among intravenous drug users including variable infectivity, HIV testing and needle exchange

Greenhalgh D., Lewis F.

Journal of Medical Informatics & Technologies

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2001

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Vol. 2, Part. 1

IP3--IP11

EN

In this article we discuss models of the spread of HIV among intravenous drug users where each infectious user progresses through three distinct phases of HIV infectivity prior to developing AIDS, and where each member of the population is randomly tested for the presence of HIV. We first begin with a brief review and literature survey before outlining the particular problems of modelling the spread of HIV through needle sharing. We then state two models, one which represents a lower bound on the spread of disease and a second an upper bound. We briefly discuss the motivation behind these models before stating an expression for the basic reproductive number. Next we examine the impact of HIV testing in our models using a range of different relative infectivity assumptions. We find that for HIV testing to be an effective control strategy then drug users must be tested regularly for HIV and also substantially reduce the rate at which they share needles once aware of being infected.

5

HIV Testing as an Effective Control Strategy against the Spread of AIDS among Intravenous Drug Users

Lewis F., Greenhalgh D.

Archives of Control Sciences

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1999

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Vol. 9, no. 1/2

69-96

EN

In this article we examine the impact on the spread of HIV caused by regularly testing members of a needle sharing population for the presence of disease. We develop a model of injecting drug use which contains two classes of addicts, a class who are unaware of their infectious status and a class who are aware that they are infectious through having had an HIV test. We expect addicts in the latter class to participate in needle sharing far less frequently than other addicts. We begin the paper with a brief review and literature survey followed by the derivation of a model which includes both needle exchange and HIV testing control measures. We perform an equilibrium and stability analysis on our model and find that there is a critical threshold parameter Ro which determines the behaviour of the model. If Ro ≤ 1 then irrespective of the initial conditions of the system HIV will die out in all addicts and all needles. If R > 1 then this disease free equilibrium becomes unstable and if initially present disease will now persist indefinitely, moreover there now exists a unique endemic equilibrium solution which is locally stable. Finally we examine the effectiveness of HIV testing using two different performance measures for a variety of different behavioural parameters. We find that HIV testing can be a very effective control strategy if addicts are tested regularly and once aware of their infectious status they substantially reduce their rate of needle sharing.