FRED (A Framework for Reconstructing Epidemiological Dynamics) is a freely available open-source agent-based modeling system for exploring the spatial and temporal patterns of epidemics.
This page shows possible outbreaks following the introduction of a single measles case in selected US cities. The model shows the importance of a high vaccination rate in providing protection for the entire community.
FRED simulates the spread of infectious disease through an artificial population that accurately represents the demographic and geographic distributions in a given city or state, including realistic household, school, and workplace social contact patterns. Each simulation begins with the infection of a few people in the area, and as people interact in households, neighborhoods, schools, and workplaces, the disease may be transmitted from an infectious person to a susceptible person. Simulations are currently available for every state and county in the United States, and for selected international locations.
FRED was developed by the University of Pittsburgh Public Health Dynamics Laboratory in collaboration with the Pittsburgh Supercomputing Center and the school of Computer Science at Carnegie Mellon University.
The simulation begins with a single school-age child contracting measles, and shows the possible spread of the disease in the seven months after the initial case. Red dots show the location of infectious people, and blue dots show the location of recovered people. If more than a few cases appear, herd immunity has been lost, and the disease spreads easily. If only a few cases appear, herd immunity is still in place.
Two scenarios are shown. In one scenario, it is assumed that 80% of children 6 months old to 15 years old are immunized against measles. In the other scenario, it is assumed that 95% of children 6 months old to 15 years old are immunized against measles. In most cases, the difference between the 80% coverage scenario and the 95% coverage scenario is quite dramatic. This shows the importance of a high vaccination rate in providing protection for the entire community.
This work is supported by the National Institute of General Medical Sciences under MIDAS grant U54GM088491 and by the Bill and Melinda Gates Foundation. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the software.