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Weeks after online searches for gut symptoms increase in an area, coronavirus cases tend to increase as well, according to a study published in the journal Clinical Gastroenterology and Hepatology.
Search data could help public health officials identify where the next U.S. hotspots may be, researchers at Massachusetts General Hospital in Boston found.
“Our data underscore the importance of GI symptoms as a potential harbinger of COVID-19 infection,” they wrote.
The research team used the Google Trends tool to look at search trends related to gastrointestinal issues, such as loss of taste, loss of appetite, diarrhea, vomiting, and abdominal pain, and the number of COVID-19 cases reported in 15 states from Jan. 20 to April 20. They followed the weekly search volume of each gastrointestinal term over the 13 weeks in each state.
A large number of gut-related searches happened in states that were hotspots — particularly New York, New Jersey, California, Massachusetts, and Illinois — about three or four weeks before a surge in cases.
Ageusia, or the loss of taste, had the highest correlation between symptom search volume and COVID-19 case volume — about four weeks later. Loss of appetite and diarrhea were also major indicators in some states.
Search term trends have been helpful in estimating the spread of other diseases as well, the authors wrote, including other infectious diseases and the flu. Previous studies have shown a lag time of about one or two weeks between online searches and the flu. The longer timeframe for COVID-19 could be related to “differences in testing availability, reporting, or longer incubation period of COVID-19 compared with influenza,” the researchers wrote.
At the same time, Google Trends data is limited and doesn’t allow researchers to look at different variables that could affect search trends or COVID-19 cases, such as demographics, occupational factors, or Internet use. Future studies could investigate the peak times for search terms and any potential seasonal fluctuations in coronavirus cases, they wrote.
Even still, “Google Trends may be a valuable tool for prediction of pandemics with GI manifestations,” they said.
Clinical Gastroenterology and Hepatology, “Increased Internet Search Interest for GI Symptoms May Predict COVID-19 Cases in U.S. Hotspots.”