Table 1.
Topics identified by LDA and NMF.
| LDA | NMF | |||
|---|---|---|---|---|
| No. | Topic/content | Keywords | Topic/content | Keywords |
| 1 | Government response | ban, travelgov, potus, dv2021, loveisnottourism, whcovidresponse, end, visa, please, vp | Government response | whcovidresponse, potus, loveisnottourism, cdcdirector, presssec, vp, cdctravel, cdcgov, liftthetravelban, cdctravel cdcdirector |
| 2 | Association for Molecular Pathology (AMP) / mask and virus | amp, travel, come, spread, mask, place, follow, stay, keep, virus | Association for Molecular Pathology (AMP) / desire to travel | covid, travel, people, amp, want, covid travel, time, travel covid, like, year |
| 3 | Rt value / India, UK, Europe | rt, travel, country, India, uk, covid, government, list, eu, news | Rt value | rt, covid, travel, https, covid19, traveler, rt ollysmithtravel, traveler, httpstco, ollysmithtravel |
| 4 | Travel restriction / England and Scotland | travel, covid, restriction, city, team, England, despite, event, expect, Scotland | Travel restriction | restriction, travel restriction, covid travel, covid19 travel, ease, covid restriction, travel, lift, covid19 restriction, restriction lift |
| 5 | Vaccination / border between Canada and the USA | vaccinate, covid19, international, traveler, travel, vaccination, Canada, border, US, fully | Travel ban / India and UK | ban, India, travel ban, travel India, uk, list, country, ban travel, red, variant |
| 6 | Quarantine and lockdown / Australia | traveler, day, quarantine, variant, allow, return, lockdown, Australia, break, two | General about travel / Canada | covid19, travel, covid19 travel, international, travel covid19, country, pandemic, international travel, vaccination, Canada |
| 7 | COVID-19 cases / USA | case, new, travel, health, state, tourism, public, number, close, include | Vaccination and quarantine | vaccinate, fully, fully vaccinate, vaccinate covid19, traveler, vaccinate traveler, traveler, quarantine, cdc, require |
| 8 | Flight / COVID-19 test | test, travel, need, positive, covid, flight, negative, air, take, airport | COVID-19 cases / New Zealand | case, new, covid case, covid19 case, new case, rise, Zealand, New Zealand, report, case covid19 |
| 9 | Death / Florida | covid, die, death, cause, florida, child, spike, shoot, traveler002, flu | COVID-19 test | test, covid test, negative, positive, test travel, test positive, PCR, covid19 test, day, result |
| 10 | China and USA | travel, covid, call, china, business, 2020, trump, usa, dr | Vaccination pass | vaccine, covid19 vaccine, covid vaccine, passport, vaccine passport, require, vaccine travel, dose, mandate, vaccination |
| 11 | Unspecific I | not, covid, vaccine, people, do, travel, get, make, still, would | ||
| 12 | Unspecific II | travel, may, covid, 2, please, 1, help, show, 3, pass | ||
| 13 | Unspecific III | covid19, travel, due, pandemic, world, today, first, update, coronavirus, safe | ||
| 14 | Unspecific IV | covid, be, go, travel, time, get, want, one, year, see | ||