POLYMOD

EC contribution

: € 1 613 500

Duration

: 48 months

Starting date

: 01/09/2004

Instrument

: STREP

Keywords

: modelling infectious diseases; contact patterns; health economics; policy evaluation

Project Number

: SP22-CT-2004-502084

Web-site

: http://venice.cineca.org/polymod.html

Problem:

Mathematical models are increasingly used to estimate the impact of control programmes against infectious diseases. The accuracy of model predictions depends on the quality of the data used to parameterise them. Contact patterns between individuals are critical to the spread of many infectious diseases (e.g. as influenza, TB, smallpox, meningitis etc). However, very little is known about the relevant contact patterns. Instead, analysts have assumed certain contact patterns based on very little (or no) data. Clearly, this affects the reliability of predictions and the policy advice that follows from this.

POLYMOD aims to collect relevant contact pattern data, improve mathematical models, use these models in economic analysis, and then convey the results to policymakers.

Aim:

To improve public health decision-making, through improved mathematical models of the spread of infectious diseases.

Results:

Highlights of the results are presented here.

Figure 1. Age-specific contact matrices for different European countries. White colour indicates high contact rates, green intermediate contact rates and blue colour indicates low contact rates, relative to the countryspecific contact intensity. Data were presented in Mossong et al., PLoS Medicine, 2008.

Figure 1 summarises the age-dependency in contact patterns observed in the eight different countries that performed a survey. It is clear that contact patterns tend to be highly correlated with respect to age (people tend to contact others that are similar in age to themselves) and that this is particularly true for children and young adults. This has particularly important implications for vaccination programmes, which are often targeted at one age group, but may have an impact on other ages. Furthermore, it is very important for understanding the spread of emerging pathogens, such as pandemic influenza, and the potential impact of various control measures, including school closure. It is also very noticeable that contact patterns are similar in different European countries, suggesting that it may be able to extrapolate from these surveys to other countries. Full details of the results are given in Mossong et al. 'Social contacts and mixing patterns relevant to the spread of infectious diseases', PLoS Med, 2008, Mar 25;5(3):e71.

Utilising these contact patterns new models of VZV transmission have been developed and have been used to predict the impact of vaccination. The results of these models are being fed into economic analyses, and are being presented to decision-makers.

Figure 2. The estimated cost-effectiveness of rotavirus vaccination in 5 different European countries (data from Jit et al. unpublished).

Figure 2 gives an example of the costeffectiveness of rotavirus vaccination in a number of different countries (Jit et al., unpublished). The results suggest that rotavirus vaccination may not be cost-effective at current vaccine prices.

Potential applications:

POLYMOD should lead to improved decisionmaking in the area of infectious disease control. The results generated are directly applicable to a wide range of diseases, including gastrointestinal diseases, vaccine-preventable diseases, and emerging infectious diseases, such as pandemic influenza.

Coordinator:

Partners: