The spread of viruses is a complicated function of several factors, including biological properties, preventative measures such as sanitation and masks, the environment, and the level of physical proximity. Governments can control this last factor through social-distancing directives. However, with a pandemic like COVID-19, data is always lagging and biased because it can take a week or more for a patient to be infected with SARS-CoV-2 and be recorded as positive.
As a result, there may be a time lag of several weeks between the implementation of a regulatory measure and its observed effect. As a result, there is an urgent need for real-time information on the level of physical proximity while maintaining personal privacy.
The pilot experiment of a virtual token, a collaboration between researchers at the University of Auckland and universities in Australia, the Netherlands, and the United States. The virtual token app spreads harmless tokens among smartphone users using Android phones and Bluetooth to better understand the relationship between physical mobility and epidemic spread.
Following the rapid Auckland lockdown, the virtual token experiment is already giving signals showing that the lockdown works to inhibit the spread of both Covid-19 as well as the virtual token strands.
The virtual token was created to assist public health officials in controlling epidemics such as Covid-19 by providing real-time data on people’s general level of contact. Such real-time data could, for example, assist officials in understanding the efficacy of various regulatory measures. When participants run the virtual token app, it sends and receives Bluetooth signals, or tokens, that simulates virus spread. The app then sends a total number of ‘virtual infections’ to a server. The app’s collected data is aggregated and anonymised.
“This experiment aims to improve scientific understanding of how physical mobility and epidemic spread interact and how evolving technologies for assessing epidemic spread can be improved,” says the project leader of the project at the University of Auckland.
“The app on Android phones collects anonymised aggregated data on secure servers but is of course harmless. This data can provide epidemiologists with real datasets that should be a great resource for policymakers to beat future pandemics early on.” In the real world, the spread of an epidemic like Covid-19 is a complicated function of multiple factors such as biological properties, preventative measures like sanitation and masks, the environment, and the level of physical proximity between people.
Unlike contact-tracing apps, the virtual token does not record any information about the identity of people who encounter a participant; instead, it simply records whether their devices have received one or more virtual tokens (if they are also running the app). But, more importantly, it transmits this data in real-time to a central database. This gives it a significant advantage over contact tracing apps in terms of understanding how an epidemic spread in a population. Contact tracing apps report more detailed information on the identities of contacts but much later if the owner of a device tests positive.
The virtual token app was designed to respond to contacts in the same way that a real virus would, but only a small percentage of the population would need to participate for the app to provide reliable predictions about the effect of social distancing on virus transmission.
After five days of lockdown, the system’s live measurements show that the number of exposed participants is decreasing, which is reflected in the number of incubating participants. The number of infected participants, on the other hand, remains constant.
Even though it is impossible to measure exposed cases in Covid cases, the effect of the lockdown on actual case numbers in New Zealand is not yet visible. The virtual token will allow citizens to see the actual effect of lockdown measures in the subset of the population that has the app on their devices.