Utilizing Baidu Index to Track Online Interest in Influenza During the COVID-19 Pandemic in China.

Background Influenza is commonly called the flu which is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and sometimes the lungs, usually a self-limiting, febrile disease of global importance. It occurs every year and infects the respiratory tract and can lead to sporadic, local outbreaks of widespread epidemics. The global burden of influenza epidemics on incidence rate and mortality is considerable. It is noted that patients with early coronavirus disease-2019 (COVID-19) have symptoms such as headache, nasal congestion, sneezing, and cough, which are like those of influenza. And the outbreak of COVID-19 coincided with the winter and spring season in the northern hemisphere with a high incidence of influenza. And it leads to the public's attention to influenza. Method In order to better clarify the social concern of Chinese people about "influenza" during the COVID-19 pandemic, this study conducted a trends analysis using the Baidu index from January 1, 2018, to January 1, 2022, and compared the public's search index with "COVID-19" during this period. This study used ArcGIS version 10.4 (https://www.esri.com/) to conduct a Global Moran's I analysis of the public concern of "influenza" in 31 provinces (municipalities directly under the central government and autonomous regions) in China from 2018 to 2021, except for Hong Kong, Macao, and Taiwan and a Local Moran's I of the "influenza" concern in 2018 and 2021. Results We observed that before the outbreak of COVID-19, the search trend of the public for "influenza" was concentrated in the winter and spring of each year, showing seasonal characteristics. However, after the outbreak of COVID-19, the public's search trend for "influenza" increased sharply, and then it leveled off. This shows completely that there is a certain correlation between the COVID-19 outbreak and the online search for "influenza". Regarding the Global Moran's I, the spatial clustering of national "influenza" concerns was observed. During the COVID-19 pandemic, the spatial correlation between the magnitude of public concern and the spatial correlation became larger as the number of years increased and is greater than that before the outbreak of the COVID-19 pandemic. The results of Local Moran's I showed that the main types of local spatial autocorrelation in 2018 and 2021 were both positive high-high correlations, but the former was mainly concentrated in the eastern coastal region, while the latter began to spread to the central region. Conclusion The analysis of the Baidu Index shows that during the COVID-19 pandemic, the public's interest in "influenza" first increased and then decreased, and then remained at a trough, no longer showing the seasonal change characteristics before the outbreak of the COVID-19, indicating that there may be a correlation between COVID-19 and "influenza". The Moran's I indicate that the national "influenza" concern is spatially clustered, while the spatial correlation is increasing and greater than before the outbreak of the COVID-19 pandemic. This is most likely related to the daily update of information related to patients with COVID-19. Meanwhile, the "high-high" local clustering of "influenza" concerns in the central and eastern regions during the COVID-19 pandemic is related to the frequent human and logistic exchanges in the central and eastern regions, which contributed to the spread of the disease.