Taiwan is making a Covid-19 shot to fasten up its inoculation program as the island struggles to get enough vaccine doses to vaccinate its population. The Taiwanese Covid-19 vaccine which will be produced locally comes from Medigen Vaccine Biologics and has already started rolling out last week.

Taiwan’s President Tsai Ing-Wen received her first shot of the two-dose vaccine last Monday. The Taiwanese vaccine was developed by Medigen in collaboration with the National Institutes of Health in the U.S. The vaccine is based on recombinant protein, which is a technology that uses a part of the coronavirus protein to alarm an immune response.

In the last few weeks, over 600,000 people in Taiwan have received the Medigen shot according to the company’s Chief Executive Charles Chen.

However, critics have appeared regarding the approval of Medigen’s vaccine. The country’s health authorities approved the vaccine for emergency use in July but it came quickly as the vaccine has only passed the phase two clinical trials in Taiwan without any efficacy data available.

Chen told CNBC that it was not possible to conduct a “traditional efficacy trial” because Taiwan’s infection rate is “so low.” Such a trial typically involves a comparison between a vaccinated group and a control group that does not receive the vaccine, he explained.

Instead, Medigen used a method called “immunobridging” to infer the vaccine’s protection level based on the immune responses in trial participants.

“We will say that our protection will be ... the same or even better than AstraZeneca,” said Chen.

Medigen said in July that it received approval to conduct a phase three clinical trial for its Covid vaccine in Paraguay.

Taiwan struggles with vaccine deliveries

Taiwan’s vaccination program started slowly with the Covid vaccine deliveries challenges hitting the whole world. The island has about 24 million people but they only received 10 million doses of Moderna and AstraZeneca vaccines according to public data compiled by Unicef. That includes nearly 6 million doses donated by the U.S. and Japan, the data showed.