Hong Kong has a Covid-19 lockdown in place (Jan 8th - Jan 21st, 2022) for flights from Australia, Canada, France, India, Pakistan, the Philippines, UK and the USA.
https://www.hellenicshippingnews.com/hong-kong-bans-flights-…
I wonder if Hong Kong knows that the Covid virus does not carry a passport. What if a traveler from one of the banned countries happened to make a transit stop e.g. in Tokyo or Singapore. Could that traveler continue onto Hong Kong?