An outbreak usually begins with sparse, delayed, and incomplete observations from a small number of locations. By the time conventional time-series indicators clearly show sustained growth, opportunities for early intervention may already be disappearing. Could changes in the structure and activity of the underlying transmission network provide earlier warning that an outbreak is shifting from localized transmission toward regional or wider expansion?
We propose studying outbreaks as dynamic, directed, multiscale graphs. Nodes could represent geographic areas, populations, healthcare systems, or host groups. Time-varying edges could represent mobility, contact, transportation, inferred transmission, or genetic relatedness. Signals observed on the nodes could include cases, hospitalizations, wastewater measurements, syndromic surveillance, and genomic indicators.
The working group would identify structural-temporal warning signals—such as changes in connectivity, directionality, community boundaries, or bridge populations—that precede expansion. A central question would be whether these signals transfer across pathogens, locations, spatial resolutions, and surveillance systems. Retrospective studies would simulate real-time emergence by restricting the information available at each point in an outbreak.
Graph-based approaches would be evaluated against time-series-only methods, static-network approaches, established epidemiological models, and ensemble forecasts. The group would explicitly study missingness, reporting delays, changes in surveillance, uncertainty, and negative transfer: situations in which a pattern learned from one outbreak produces misleading conclusions in another.
We seek interpretable principles for when network structure adds actionable information, when evidence from previous outbreaks can be reused, what additional observations would reduce uncertainty, and when a model should abstain from issuing an alert.
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