A man receives a dose of a vaccine against the coronavirus disease at St. Paul's Church in Abu Dhabi, United Arab Emirates on Jan 16, 2021. [Photo/Agencies]

A sample image of a digital health certificate for international travelers on the WeChat mini program. [Photo provided to China Daily]

Passengers line up to check in at the Tianjin Binhai International Airport in Tianjin, on Jan 28, 2021. [Photo/Xinhua]