The Chinese government is requiring all foreigners to get its domestic-brand COVID-19 vaccine before entering the country — a move that could have grave consequences for any future travel to and from North Korea, according to analysts.

Even before North Korea first locked down its borders as a COVID-19 prevention measure in Jan. 2020, most travel to and from North Korea involved transit through Chinese territory. But China’s foreign ministry issued new visa guidelines on several embassy websites on Tuesday, stating that applicants for a range of visa types would first need to be “inoculated with Chinese COVID-19 vaccines” in order to apply to enter China.