英文關鍵字
virus
coronavirus
travel
medical
pandemic
airport
health
covid
international
quarantine
test
medicine
tourism
corona
covid19
epidemic
security
person
technology
border
disease
global
infection
sick
immigration
passenger
danger
tourist
traveler
digital
application
certificate
document
identification
immune
immunity
mask
online
prevention
safe
screen
show
transportation
vaccination
vaccine
app
direction