A method may include receiving data about a first person and a second person, the first person having a contagion. The method may include determining whether a first location is within a proximity distance to a second location. The method may include determining whether a first time is within a proximity time period with a second time. The method may include defining a proximity relationship for the second person relative to the first person. The defined proximity relationship may be positive when the first location is within the proximity distance and first time is within the proximity time period, or the defined proximity relationship may be negative when either the first location is not within the proximity distance or first time is not within the proximity time period. When the proximity relationship is positive, the second person may be labeled as being contaminated by the contagion.