Table 4.

The top 15 ranked feature words of 5 topics (Twitter dataset)

No	Feature words	Name
1	Gov; Trump; Announce; United states; White house; Notice; USA; Washington; Coronavirus; California; York; Georgia; Close; Mike Pence; Breaking	US States authorities’ announcements
2	Confirm; Report; Rise; Philippines; Death; Case; Outbreak; South; Italy; Lockdown; Korea; Total; Official; Country; Flu	Cases and death
3	CDC; Hongkong; Japan; Diamond Princess; Cluster; Japanese; Ship; Cruise; Passenger; America; Infect; News; Biden; Virus; China	Diamond Princess cruise ship outbreak
4	China; Wuhan; Coronavirus; Chinese; Covid-19; CDC; Hongkong; Coronavirusoutbreak; Corona; Hubei; Beijing; Trump; Corona virus; Outbreak; Cemocrats	China and Wuhan outbreak
5	Spread; Lockdown; France; Mask; US; Patient; Australia; Vietnam; Singapore; Hospital; Test; Discharge; Nucleic acid; Report; Viral; Medical institution	Preventive measures

No topic identification number