London School of Hygiene & Tropical Medicine

A nationwide experiment that simulated the spread of a highly infectious disease has generated vital new information which will help pandemic researchers prepare for potential global outbreaks.

Involving scientists from the London School of Hygiene & Tropical Medicine and the University of Cambridge, Contagion! The BBC Four Pandemic used smartphone data to reveal how nearly 30,000 people moved about in the UK and interacted with others.

Flu outbreaks occur every year but in the last 100 years, there have been four pandemics, including the particularly deadly Spanish Influenza outbreak which hit in 1918, killing up to 100 million people worldwide. Nearly a century later, a catastrophic flu pandemic still tops the UK Government’s Risk Register of threats to this country.

Key to the Government’s response plan are mathematical models which simulate how a highly contagious disease may spread. These models help to decide how best to direct NHS resources, like vaccines, antivirals and protective clothing - but the models are only as good as the data that goes into them.

To improve the available data before the next pandemic strikes, the BBC teamed up with LSHTM and the University of Cambridge to create a smart phone app. The BBC Pandemic app anonymously tracks approximate movements and records contacts of volunteers who download it, creating the biggest dataset of movement and contact details for UK pandemic research ever collected.

Dr Adam Kucharski, Assistant Professor in Mathematical Modelling at the London School of Hygiene & Tropical Medicine, who helped design the study, said: "The results of the BBC Pandemic experiment have been astonishing. We set the BBC the challenge of getting 10,000 people around the country to download the app, but the number of downloads have exceeded expectations.

“Usually we can only dream of having access to such high resolution information. It means we can look in far more detail at how a flu pandemic might spread through the UK, and what the impact could be."

The BBC 4 documentary – presented by mathematician Dr Hannah Fry and Ebola physician Dr Javid Abdelmoneim – discusses results from the National Outbreak, open to anyone in the UK, and a closed local study only open to people in the town of Haslemere, Surrey. This data was used to model the potential spread against a 'reasonable worst case' pandemic scenario similar to that in the October 2016 UK Scientific Pandemic Influenza Advisory Committee summary.

It calculated that in the worst case scenario as many as 43 million people in the UK could be infected with a potential death toll of 886,000. This assumed everyone who was infected became ill, and a case fatality of 2%.

A paper published in the journal Epidemics describes the science underlying the modelling in the television programme, and highlights the promise that this dataset holds for improving future epidemic models. To maximise potential benefits, the data will be made fully available to other researchers in early 2019, once the study finishes.

Dr Petra Klepac, Assistant Professor of Infectious Disease Modelling at the London School of Hygiene & Tropical Medicine, led the study. She said: “Being involved in the BBC Pandemic project has been a wonderful and exciting experience. The app is still gathering data, and the resulting dataset will become a new gold standard in modelling contact and movement patterns that shape the spread of infectious diseases. Perhaps equally important is that the BBC Pandemic project also engages the public in our research and increases the understanding and awareness of scientific methods that are used to make public health decisions.”