Table 2 Selected themes and topics for Rolling-ONMF and Sliding-ONMF

From: What Are People Concerned About During the Pandemic? Detecting Evolving Topics about COVID-19 from Twitter

Selected themes Rolling-ONMF topics Rolling-ONMF Sliding-ONMF topics Sliding-ONMF
   Weeks range   Weeks range
COVID-19-related Conspiracy theories about Bill Gates 19, 20 Hairstylist in Missouri infected with COVID-19 23
Events Florida scientist fired over COVID-19 16 does not infect customers 17, 18
  dashboard 25 Pope Francis mass 10, 11
  The pandemic and BLM protests 16–26 SXSW festival in Austin cancelled 16, 17, 18
  father’s day during lockdown 26 Together at home concert 10, 11
    Toilet paper and hand sanitizer shortages  
COVID-19 spreading COVID-19 spreads from China to NY 10, 11 Asymptomatic spread of the virus 24
  the pandemic in 3rd world countries 25, 26 Attempts to slow down the virus  
    spread are not successful 10–14
    COVID-19 spreads from China to Iran and Italy 10, 11, 12
COVID-19 testing A plea for people to get tested 24, 25, 26 Insufficient testing in the USA 10, 11
    PPE and adequate testing for frontline workers 19
    Drivethru testing in South Korea 13
COVID-19 updates COVID-19 daily news update 10–13 Increase in cases of younger people 18, 19
  COVID-19 global alert 10–26 Total deaths and hospitalizations 10–26
  Global increase in cases 10–26 Brazil is a COVID-19 hotspot 22, 23
Economic crisis Businesses closed amid pandemic 12 Relief for small businesses 18
  Stock market crashes 11 Shut down businesses during the pandemic 14
    COVID-19 US relief package 12–26
Essential workers Essential workers and businesses 12–16   
  Support for all essential workers 19–23   
Government policy Narendra Modi’s handling of COVID-19 14 Lockdowns are extended 16
  Pandemic response in Kalinga region India 23 NY State response to COVID-19 15–26
  NY declares state of emergency 11–21 Some states begin to reopen 17
  Declaring of emergency in many countries 11–23 Trump criticizes Obama administration 22
  World leaders claim COVID-19 is a hoax 11–18 Lockdowns in multiple countries 11–14
Healthcare Hospitals lacking ventilators and other    
  resources 18–22 Kawasaki syndrome in children with COVID-19 21
  Support for healthcare workers 10–15 Patients may be reinfected 17, 18
    Protecting residents of nursing homes 17, 18, 19
Prevention COVID-19 safety measures like    
  hand washing and social distancing 21–26 Handwashing and social distancing 25
  Maintaining hygene and cleaning surfaces 21 Hashtags related to COVID-19 motivating  
  people to stay home and stay safe 10–13   
  Social distancing 12–16 Importance of wearing facemasks 26
  Stay home save lives 10–19 New staying home lifestyle 15–22
Racism    Blaming Muslims for spreading COVID-19  
    in India 26
    Chinese propaganda to hide severity of COVID-19 14–20
    Racism towards Chinese due to the pandemic 13
Vaccines and treatments Hydroxicloroquine, flu vaccine    
  and other proposed treatments for COVID-19 13–19 Bill Gates and vaccine development 22
  Studies on HCQ 22 Different experimental treatments for COVID-19 16
  Vaccine for COVID-19 21 First vaccine trial starts 13
    Oxford vaccine trial 19, 20