Web searches of COVID-19 surged week before tests
Could have been ‘canary in a coal mine’
A surge in internet searches and social-media posts about coronavirus illness came more than a week before laboratory tests in China confirmed the outbreak, suggesting search engine traffic can predict virus hotspots long before patients hit the hospital.
Had they regarded the health questions that concerned people were asking as a “canary in a coal mine,” monitoring search engine queries could have sounded a warning 10 days earlier in the cycle of the COVID-19 outbreak in China, researchers found.
“Predicting the development of the outbreak as early and as reliably as possible is critical for action to prevent its spread,” writes Cuilian Li of Shantou University in Shantou, China, the study’s lead author.
“Internet surveillance data provided an accurate and timely prediction about the outbreak and progression of COVID-19.”
The researchers’ data shows that two popular search engines and a popular social-media platform “were able to predict the disease outbreak 1–2 weeks earlier than the traditional surveillance systems.”
Time is crucial during an outbreak.
“COVID-19 is a rapidly spreading infectious disease,” the study says. “It is important to predict the development of this outbreak as early and as reliably as possible, in order to take action to prevent its spread.
“The availability of early information about infectious diseases through internet search engines and social media will be helpful for making decisions related to disease control and prevention.”
Researchers looked first at the daily numbers of new laboratory-confirmed cases and suspected cases of COVID-19 from the National Health Commission of China in the first few months of the novel coronavirus originating in Wuhan, China.
The peak of daily new laboratory-confirmed cases was on Feb. 4 and the peak of daily new suspected cases was Feb. 5.
Researchers then compared this with search inquires and social media posts made in China using Google as well as the Baidu, China’s most popular search engine, and Sina Weibo, a major Chinese
social media platform, for the weeks prior to the laboratory virus data.
The peak number of searches in Baidu for “coronavirus” and “pneumonia” (in English and in their Chinese equivalents) were both on Jan. 25. The peaks for the keywords on Google Trends were also reached on Jan. 25. The peak number of posts on Sina Weibo for the same words was even earlier, Jan. 21.
That means the peak of apparent citizen concern over a spreading viral illness was eight to 10 days earlier than laboratory-confirmed cases, and five to seven days earlier than new suspected cases.
The study was recently published in Eurosurveillance, a peer-reviewed journal on infectious disease surveillance, associated with the European Centre for Disease Prevention and Control.
Previous internet search data was able to flag the emergence of Middle East Respiratory Syndrome and the Zika virus days before laboratory confirmations.
“This study reveals the advantages of Internet surveillance using Sina Weibo Index, Google Trends and Baidu Index to monitor a new infectious disease,” the study says. “Reliable data can be obtained early at low cost.”
The study does not address privacy concerns about such monitoring.
In times past, miners would keep a nervous eye on caged canaries brought with them into a mine tunnel as an early warning of danger; deadly gases in the mine would kill the birds before the miners giving them a chance to scramble out.