News

Digital tracing apps should incorporate social connections to mitigate disease outbreaks

Researchers at Aalto University used network science to model the efficiency of digital tracing techniques.
Illustration of digital pandemic tracing networks
Digital contact tracing can help mitigate outbreaks if social network structures are incorporated into its modelling. Image: Abbas K. Rizi

To help cope with the COVID-19 pandemic, many governments rolled out digital tracing apps which notified people when they had been exposed to infection, reducing the disease’s spread via secondary infections. Widespread adoption of these apps would reduce the need for other, more severe measures, such as lockdowns. But it turns out that figuring out what level of adoption would be enough for the apps to work is a challenging problem rooted in human social behaviour. 

‘In science, we have numerous complicated problems, but social behavior is beyond complicated, it’s complex,’ says Abbas K. Rizi, Ph.D. candidate at the Department of Computer Science.

In many countries, privacy concerns reduced usage of tracing apps, watering down the impact to less than had been expected. Public discussion quickly shifted to the critical number of app-users required to mitigate the outbreak.

‘These figures are often based on modelling, which doesn't take into account the in-between structures and hubs of social interaction,’ explains Rizi. His research group recently published a study which examines the effects of varying app coverage and quarantine failures on the epidemic’s threshold, probability and expected size.

To introduce social complexity into digital tracing, the team built models that incorporated the human tendency to be in social relations with similar people, which could be related to age, occupation, wealth and nationality – a property known as homophily. They used these tools to model different scenarios, evaluating the impact of digital tracing in a variety of complex networks.

‘The number of downloads of the digital tracing app shouldn’t be the only meaningful number, but also the degree of homophily among the population that has downloaded the app.’  

The social connections of people who download the app affect the outcome. The dynamics differ dramatically when the app is used by socially active groups or people who have few social connections in their daily lives. 

‘Our model allows us to simulate when and how large an outbreak can happen even if only a fraction of the population download the app,' says Rizi.

‘The results indicate that digital contact tracing affects the course of epidemics by raising the epidemic threshold and reducing the size of emerging outbreaks. To give a good estimate of the size and the probability of an epidemic, we just need to know the network structure, how applications are distributed among the population, and how well the tracing works.’ 

Traditional models in epidemiology assume that social connections are random. Network scientists infuse their mathematical models with more realistic, although still not exhaustive, assumptions of social behavior. 

‘The way that people are wired together in society can lead to dramatic effects on the size and probability of an outbreak.'

The study was published in the Physical Review E journal, published by the American Physical Society.

  • Published:
  • Updated:
Share
URL copied!

Read more news

Tummaan paitaan pukeutunut vaalea lyhyttukkainen nainen seisoo kädet ristissä rinnan edessä, taustalla korkeakoulun tiloja
Appointments, Research & Art, University Published:

Professor Arja Karhumaa: ‘We need to better understand how texts are viewed’

Introducing our tenured professors: professor Arja Karhumaa explores the relationship between language and the visual form of a text –how a text looks at any given moment, and how it affects us as human beings.
Konsta Laakso and Elsi Sloan act in the short film of Oasis of Radical Wellbeing
Research & Art Published:

The short film filmed in Aalto tells about a student's difficult choice

The shooting of the short film Myötätunto III, funded by Aalto University's Oasis of Radical Wellbeing project, began in Otaniemi on March 17th. The premier is on May 30th as a part of the Green Minds, Healthy Hearts – Social Sustainability Symposium in Aalto University's Harald Herlin Learning Center.
Kemiantekniikan opiskelijoita
Research & Art Published:

Are you our new CHEM Data Agent?

Apply to be the next Data Agent from the School of Chemical Engineering.
Illustration: Juuli Miettilä.
Research & Art Published:

Avatars and genuine interaction

Aalto University’s researchers are contributing to the creation of redesigned maternity and child health clinics and positive childbirth experiences in their research projects. The visions seize the potential of technology, such as childbirth simulation in a 3D-video conference using an avatar, a virtual character. On the other hand, the researchers would also like to hold on to the best practices from the past, such as the traditional child health clinic card, genuine human interaction and the rotina tradition, visits by family and close-ones to meet the newborn and bring foods as a gift.