Early detection of COVID-19 pandemic: evidence from Baidu Index

Abstract Background: New coronavirus disease 2019 (COVID-19) poses a severe threat to human life, and causes a global pandemic. The purpose of current research is to explore the onset and progress of the pandemic with a novel perspective using Baidu Index.Methods: We collected the confirmed data of COVID-19 infection between January 11, 2020, and April 22, 2020, from the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU). Based on known literature, we obtained the search index values of the most common symptoms of COVID-19, including fever, cough, fatigue, sputum production, and shortness of breath. Spearman's correlation analysis was used to analyze the association between the Baidu index values for each COVID-19-related symptoms and the number of confirmed cases. Regional differences among 34 provinces/ regions were also analyzed. Results: Daily growth of confirmed cases and Baidu index values for each symptoms presented a robust positive correlation during the outbreak (fever: rs=0.705, p=9.623×10-6; cough: rs=0.592, p=4.485×10-4; fatigue: rs=0.629, p=1.494×10-4; sputum production: rs=0.648, p=8.206×10-5; shortness of breath: rs=0.656, p=6.182×10-5). The average search-to-confirmed interval is 19.8 days in China (fever: 22 days, cough: 19 days, fatigue: 20 days, sputum production: 19 days, and shortness of breath: 19 days). We discovered similar results in the top 10 provinces/regions, which had the highest cumulative cases. Conclusion: Search terms of COVID-19- related symptoms on the Baidu search engine can be used to early warn the outbreak of the epidemic. Relevant departments need to pay more attention to areas with high search index and take precautionary measures to prevent these potentially infected persons from spreading further. Baidu search engine can reflect the public's attention to the pandemic and regional epidemics of viruses. Based on changes in the Baidu index value, we can predict the arrival of the peak confirmed cases. The clinical characteristics related to COVID-19- including fever, cough, fatigue, shortness of breath, deserve more attention during the pandemic.