History tells us that human beings are sometimes unreliable (or incapable) when it comes to reporting their symptoms and recalling their movements and contacts during an epidemic – yet it is information that is vital to limit the spread of a contagious disease and make sure those exposed get treatment. Epidemiologists can also be constrained by privacy issues – despite the urgency of the situation.
Now, recent research by an international team of scientists and computer modellers has revealed how mobile phones can help limit human error or omission and be used to track the spread of a disease outbreak by analysis of the “communication traces” from text and calls.
Mobile phones are globally ubiquitous
Previous research in online social networks, such as Facebook, have found that they are of limited use in tracking epidemics, as online social behaviour can differ significantly from physical interactions, which are necessary for disease transmission to occur. However, the researchers believe that mobile phones provide a promising resource as “they are ubiquitously carried by the population, irrespectively of socio-economic status, and provide a much larger-scale, data-driven opportunity for epidemiology. Further, mobile phones are carried by people when they travel overseas, potentially serving as a global physical proximity sensor. Its pervasiveness in countries under development, where pandemic prevention is most critical, makes then a viable option,” the researchers write in their published paper.
Computer model traces university students’ contacts and movements
Working on the assumption that communication traces obtained from mobile phones would be a good proxy for a physical interaction network, the team of researchers from the University of London, Laboratoire Hubert Curien, France, MIT and National Information and Communications Technology Australia put together a computer model for contact tracing and tested it on a dataset from a group of 72 students traced over a 9-month period for which both physical interactions as well as the mobile communication traces were known. The dataset consisted of 1 973 547 Bluetooth interactions, 10 992 phone call records and 9432 SMS records, with the students representing 80% of the total population of an undergraduate dormitory in a North American university.
Contact tracing most efficient at the beginning of an outbreak
“Our results suggest that a wide range of contact tracing strategies may significantly reduce the final size of the epidemic, by mainly affecting its peak of incidence. However, we find that for low overlap between the face-to-face and communication interaction network, contact tracing is only efficient at the beginning of the outbreak, due to rapidly increasing costs as the epidemic evolves.
“Overall, we find interactions sensed by mobile phones to be a promising tool for epidemic simulation, particularly for future large-scale scenarios; for example, city-scale infectious disease transmission. This work demonstrates mobile phone communication history to be a useful data source in disease prevention by obtaining contact information readily for epidemic contact tracing,” the researchers write in their published paper.
The results of the research were published in 2014 by the open-access science journal PLoS ONE.
This student activity demonstrates how a viral disease can spread through a population, even if an individual only comes in contact with three other people.
Farrahi, K., Emonet, R. and Cebrian, M. (2014). Epidemic contact tracing via communication traces. PLoS ONE. doi: 10.1371/journal.pone.0095133. Open-access article available from