Section 1: Introduction (from DOI:10.14218/ERHM.2020.00023)
Section 1: Introduction
Coronavirus disease 2019 (COVID-19) has been pandemic in the world.1–4 It has now affected more than 560,000 Americans.3,5 Several attempts were successfully made to model COVID-19 daily incidence in China.1,6 However, the trends of daily incidence and deaths of COVID-19 in the USA are still poorly understood. Recently, internet search-interest was found to be correlated with daily incidence of COVID-19 in China, with the lag time of 8 to 10 days.7 Google search-interest was also used to track or model COVID-19 trends in Europe, Iran, and Taiwan.8–10 Indeed, internet search-interest has been used for modelling and detecting influenza epidemics in the USA and Australia.11,12 We, therefore, aimed to examine the association of search-interest with daily incidence/new cases and deaths of COVID-19 in the USA, using population-based data and a semiparametric model.