If you’re anything like the average person, you’ve likely been heading to Google, tapping in search queries like “coronavirus symptoms” at the first sign of a sniffle or cough in the last few months.

Search engines have become digital confession booths – and as governments grapple with the scale of an international pandemic tearing through countries at an unprecedented rate, they’re recognising the power of those queries as an early warning tool for public health outbreaks.

“You can think about it as a window onto the collective consciousness onto the part of humanity that uses search engines,” said Sam Gilbert of the Bennett Institute for Public Policy at Cambridge University, which works at the intersection of technology and public policy.

Faced with a pandemic about which most health experts still know very little, and confronting a mounting death toll, governments have started embracing the power of search

Such infodemiology – a portmanteau of “information epidemiology” – has been used by private companies since 2008, when Google launched its Flu Trends model, analysing online searches to see if there was the presence of flu-like symptoms in a population. But it has taken longer for governments and their health agencies to adapt the data to look at public policy interventions – and not just for healthcare.

As with many things, the coronavirus has sent years of glacial progress into hyperdrive. Faced with a pandemic about which most health experts still know very little, and confronting a mounting death toll, governments have started embracing the power of search.

Search queries had been used to track how Ebola spread through West Africa in 2014, how West Nile fever moved through Italy and how Zika ravaged Brazil in 2016. But when identifiable symptoms of COVID-19 began to be established, including the loss of smell, governments began to realise they could better track the spread of the coronavirus through what people typed into search engines than their often-stuttering track and trace systems.

The UK is one country that has struggled to develop a reliable contact tracing system for coronavirus, and that has rolled out testing but is nowhere near widespread enough to be able to accurately monitor the spread of the disease. So Public Health England (PHE) is looking instead at search queries.

“According to PHE, estimates from these models provided important insights about community transmission,” explained Bill Lampos, a computer scientist at University College London, who is analysing online search activity – mitigated by the impact of news media – to try and track the spread of COVID-19. Lampos’s data has been successful: “Traditional surveillance methods were not as effective because testing was restricted to hospitalised cases,” he said.

An analysis of the data by Lampos and his team shows that online searches across eight countries provide advance warning of COVID-19 outbreaks 17 days ahead of them happening when compared to the reported confirmed cases in a country.

His research is now put into PHE’s weekly reports on the spread of coronavirus, alongside transport data collected from Apple and Android phones, to try and get a better picture of how the country is reacting to the pandemic.

"Think about it as a window onto the collective consciousness onto the part of humanity that uses search engines"

But the use of such data doesn’t have to stop at tracking COVID-19’s pernicious spread. “It’s also possible to look at this enormous ocean of data that’s been created by people’s Google searches and understand better what people think about public health,” said Gilbert. The wealth of search data can be used for a range of other health issues. Lampos suggests it could be harnessed to track mental health concerns or raise early warnings about cancer symptoms.

It could also be a tool for policy development. “People’s searches aren’t just about products or health, but might be about benefits,” said Gilbert. “Because of the current circumstances in the UK, there’s been significant changes around things like Universal Credit that can inform policy.” Google search results – which people conduct in the privacy of their own homes, with their own thoughts, away from the prying eyes of others – are likely a better barometer of public opinion than thousands of surveys and reams of polling.

At present, harnessing their power isn’t happening. “I don’t think government has particularly tuned into those searches – nor would I expect them to,” says Gilbert. But as we transact more and more of our lives online, and as the connection between the state and its people becomes more remote, it’s important that those in power keep a connection with the public – and this may be the only feasible way to do so. – Chris Stokel-Walker

(Photo credit: Nathana Reboucas/Unsplash)