Web search tools are widely used by the general public to obtain health-related information, and analysis of search data is often suggested for public health monitoring. We analyzed popularity of searches related to smell loss and taste loss, recently listed as symptoms of COVID-19. Searches on sight loss and hearing loss, which are not considered as COVID-19 symptoms, were used as control. Google Trends results per region in Italy or state in the US were compared to COVID-19 incidence in the corresponding geographical areas. The COVID-19 incidence did not correlate with searches for non-symptoms, but in some weeks had high correlation with taste and smell loss searches, which also correlated with each other. Correlation of the sensory symptoms with new COVID-19 cases for each country as a whole was high at some time points, but decreased (Italy) or dramatically fluctuated over time (US). Smell loss searches correlated with the incidence of media reports in the US. Our results show that popularity of symptom searches is not reliable for pandemic monitoring. Awareness of this limitation is important during the COVID-19 pandemic, which continues to spread and to exhibit new clinical manifestations, and for potential future health threats.
Bibliographical noteFunding Information:
We thank the Center for Interdisciplinary Data Science Research, The Hebrew University, for support, Maria Veldhuizen and Yuri Estrin for discussions, and Noam Lahav and Eitan Margulis for help in the initial stages of this project. MYN is funded by ISF grant #1129/19 and is a member of COST actions Mu.Ta.Lig (CA15135) and ERNEST (CA18133). FF thanks the financial support of the S.A. Schonbrunn Fellowship Fund. MYN, KA, FF and JF are members the Global Consortium of Chemosensory Research, the GCCR. This work was supported in part by Edmond de Rothschild foundation.
© 2020, The Author(s).