China said giving coronavirus vaccines still being tested to hundreds of thousands of people outside of clinical trials is justified given the risk of COVID-19 returning through its borders and the lack of any significant side-effects so far from the shots.

In July, the country authorized the emergency use of three vaccines developed by local firms China National Biotec Group Co. and Sinovac Biotech Ltd. to frontline workers, including medical staff treating virus patients, and to border officials.

But that has since been widened to include employees of state-owned companies, and the government is also considering offering experimental jabs to students heading overseas to study. Sinovac, whose CoronaVac jab began final-stage clinical trials three months ago, is allowing members of the public in at least two Chinese cities to register to receive the vaccinations, as well. The expansion has been criticized by experts, with some saying it was dangerous and a misuse of the program.