Should the slate from Nanning to Gaozhou be isolated?

No need. As of September 25, 2022, in places with low epidemic risk: if you plan to leave the area by train, you don't need nucleic acid testing, as long as you have the "health code" green code. If you want to enter the area from the local station by train, people in low-risk areas do not need a 48-hour negative report of nucleic acid testing, and passengers in high-risk epidemic areas need to provide negative results of nucleic acid testing. In addition, people in some high-risk areas will be isolated for a period of time after entering the local area from the local railway station.