Internet searches on GI symptoms predicted Covid-19 hotspots in US, says study

Researchers at the Massachusetts General Hospital (MGH) compared the volume of Internet searches on certain gastrointestinal symptoms with the reported incidence of Covid-19 in 15 states between January 20 and April 20, 2020.

They found that searches on ‘ageusia’, ‘loss of appetite’, and ‘diarrhoea’ correlated most strongly with the rise in Covid-19 cases in five high-incidence states, as per the study published on the official website of MGH.

Researchers noted in their study that as the lag time between search volume and Covid-19 incidence increased, correlation increased, with the strongest relationship at three to four weeks.

For the study, researchers analysed data gathered from the five states with the highest burden of Covid-19, i.e. New York, New Jersey, California, Massachusetts, and Illinois.

The maximum correlation between search interest and Covid-19 cases was: 0.998 for ageusia; 0.871 for loss of appetite; and 0.748 for diarrhoea.

Researchers further said that the timeframe of four weeks yielded the “strongest correlation between symptom search volume and Covid-19 case volume”.

Kyle Staller, director of MGH’s gastrointestinal motility laboratory, wrote in the study: “Our data underscore 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.”

Researchers used Google Trends data, Harvard Dataverse, and previous research on Covid-19 to identify common GI symptoms for their study.

“While our study provides information about popular search terms and their relationship to incidence, it is important to note that the relative nature of Google Trends data does not allow for defining specific increased interest thresholds,” researchers added.