Before revision:  Through Twitter 's standard search application programming interface , we retrieved over 63 million coronavirus-related public posts from more than 13 million unique users since 28 January to 1 July 2020. Using natural language processing techniques and machine learning based algorithms, we annotated each public tweet with seventeen latent semantic attributes, including :
After revision:  Through Twitter 's standard search application programming interface , we retrieved over 63 million coronavirus-related public posts from more than 13 million unique users using four keywords: "corona", "wuhan", "nCov" and "covid". Leveraging natural language processing techniques and machine learning based algorithms, we annotated each public tweet with seventeen latent semantic attributes, including :