A Chinese pharmaceutical company has injected hundreds of thousands of people with experimental Covid-19 vaccines, as its Western counterparts warn against administering mass vaccinations before rigorous scientific studies are complete.

China National Biotec Group Co., a subsidiary of state-owned Sinopharm, has given two experimental vaccine candidates to hundreds of thousands of people under an emergency-use condition approved by Beijing in July, the company said this week. Separately, Chinese drugmaker Sinovac Biotech Ltd. said it has inoculated around 3,000 of its employees and their family members, including the firm’s chief executive, with its experimental coronavirus vaccine.

The three vaccine candidates are still undergoing Phase 3 clinical trials, which involve testing a vaccine’s safety and effectiveness on thousands of people. Six other leading Covid-19 vaccine candidates are also in this final phase, according to the World Health Organization.