Title page
Contents
Executive summary 4
Acknowledgements 6
Background and justification 7
Guidance for cluster investigation 9
Overview of guidance 9
Definitions 10
Steps of a cluster investigation 11
Overview of the process ̶ flowcharts 11
Stage 1: Screening 14
Stage 2: Assessment (statistical analysis and check for biologic plausibility) 17
Stage 3: Aetiological investigation 23
Resources to aid cluster investigations 26
The Imperial College (SAHSU) Rapid Inquiry Facility (RIF) 26
SaTScan 27
DotMapper 27
Geographical Information Systems (GIS) 28
HPZone mapping function 28
Reporting results and communicating risk 29
References 32
Appendix A: Cluster investigation protocol - suggested membership of investigation teams 35
Appendix B: Tool kit: Roles and responsibilities for cluster investigation team members at each stage of the investigation process 37
Appendix C: Examples of cluster investigations carried out 40
Appendix D: Data sources 43
Glossary 45
Figure 1. Process of cluster investigation 12
Figure 2. Overview of the staged Stepwise Cluster Approach, showing parallel tracks of health, exposure assessment and communication. Adapted from guidance developed by the Health Council of the Netherlands (2001) 13