The United States will require visitors from China or who have been there in the previous 10 days to provide a negative Covid-19 PCR-RT or antigen test before departure to the country for arrivals from January 5, 2023.
China has removed domestic covid-related restrictions, including testing and reporting, and will no longer require quarantine for international arrivals from January 8, 2023.
China is going through its first significant covid-wave, which will likely result in 1 to 2 million dead, but the central government has stopped all reporting (no covid related deaths).
There is a possibility that a new strain will emerge and, as a result, many countries will now try to prevent spreading on their shores.
Conclusion
Due to the extremely high number of positive cases over the past month, there will likely be new obstacles for travelers from China or those who have recently been there.
These pre-departure covid-tests do not prevent new strains from spreading but will probably result in fewer imported positive covid-cases.