Google trends of GI symptoms may be ‘harbinger’ of COVID-19
Analysis of Google search trends correlated with increases in COVID-19 cases several weeks before any actual spike, according to study results.
Kyle Staller, MD, MPH, of the division of gastroenterology at Massachusetts General Hospital, told Healio Gastroenterology that search data have previously been linked with seasonal influenza epidemics, so he and his colleagues applied the same thinking to the GI symptoms related to COVID-19.
“We know that many patients with COVID-19 develop GI symptoms early in their course, often before manifesting more typical respiratory symptoms,” Staller said. “We were curious if internet search data would bear a similar story such that people would search these symptoms as they occur, thereby giving us an insight into disease incidence before respiratory symptoms develop and they undergo formal testing.”
Researchers used Google Trends to measure the interest in specific GI-related symptoms of COVID-19 (ageusia, abdominal pain, loss of appetite, anorexia, diarrhea and vomiting) alongside data from Harvard Dataverse to measure the true incidence of the disease. They explored incidence data from 15 states with top, median and lowest COVID-19 burden for a 13-week period from Jan. 20 to April 20, 2020. They compared the search volume for each GI symptom with reported incidence of COVID-19 for each state using time-lagged cross correlations.
Staller and colleagues found that search interest in ageusia, loss of appetite and diarrhea increased 4 weeks prior to the rise in COVID-19 cases for most states. Plots of symptoms vs. cases over time demonstrated an increase in search volume followed by an increase in COVID-19 cases after 3 to 4 weeks.
“During the height of the first wave of the pandemic in the U.S., we found that COVID 'hot spots' such as New York saw a predictable spike in searches for GI symptoms 3 to 4 weeks before increases in official case counts,” Staller said. “In states with lower COVID burdens, these relationships were less robust, suggesting a dose-response relationship.
“Although preliminary and no substitute for true epidemiologic data, this readily-available resource underscores the importance of GI symptoms as a potential harbinger of COVID-19 infection and suggests that Google Trends may be a valuable tool for prediction of pandemics with GI manifestations.”