BEIJING -- All of the COVID-19 vaccines developed by China, including both those currently in use and those pending approval, have now embarked on clinical trials, a Chinese health official said at a press conference Tuesday.

China's vaccines fall into five technical categories: inactivated vaccines, adenovirus-based vaccines, recombinant protein vaccines, live attenuated influenza vaccines, and nucleic acid-based vaccines.

Among them, three inactivated vaccines have been approved by China's medical-products administration for conditional marketing and two for emergency use, said Zheng Zhongwei, an official of the National Health Commission, who is also head of the working group for vaccine development under the State Council joint prevention and control mechanism against COVID-19.

One recombinant protein vaccine has been authorized for emergency use, and one adenovirus-based vaccine was approved for conditional marketing, according to Zheng, adding that clinical trials are being conducted on some other vaccines in the two categories.

For live attenuated influenza vaccines and nucleic acid-based vaccines, including an mRNA vaccine and a DNA vaccine, clinical trials are also conducted and the vaccines are expected to carry out phase-3 trials overseas, the official said.