China National Biotec Group (CNBG) and Sinovac Biotech Ltd said on Saturday four more countries have agreed to run late-stage clinical tests of their coronavirus vaccine candidates, as China steps up its efforts in the global race.

Serbia and Pakistan are among the new countries agreeing to Phase 3 trials, as the two companies seek more data overseas amid dwindling new cases in China.

Serbia will test two vaccines developed by CNBG’s Wuhan and Beijing units, and Pakistan will test the Beijing unit’s candidate, the company told Reuters.

CNBG’s Phase 3 trials are expected to involve 50,000 people in about 10 countries, said CNBG vice president Zhang Yuntao. Trials have already begun in United Arab Emirates, Bahrain, Peru, Morocco, Argentina and Jordan.

Zhang said foreign countries have expressed interest in ordering a combined 500 million doses of its vaccines.

CNBG is expected to be able to produce 300 million doses of vaccine a year once it upgrades manufacturing techniques, and is working on a plan to raise its annual capacity to one billion doses, Zhang said.

Sinovac’s vaccine candidate CoronaVac, being tested in Brazil and Indonesia, also obtained approvals from two other countries for Phase 3 trials, said Helen Yang, senior director of global strategy and business development at Sinovac.

She declined to name the countries as the information is still confidential.

While the final stage of trials is still underway to prove the vaccines are safe and effective, China has already authorised the vaccine candidates from Sinovac and CNBG for emergency use for those in high-risk groups such as medical workers.

Several tens of thousand people have already taken CoronaVac through the emergency programme, Sinovac’s Yang said.

CNBG will soon begin providing its vaccines to Chinese staffers working in overseas embassies and consulates, Zhang said.