China granting emergency use of its self-developed recombinant protein subunit vaccine against COVID-19 will add another weapon in the arsenal of the global fight against the pandemic, the vaccine's key scientist said on March 21.

The vaccine was developed by the Institute of Microbiology of the Chinese Academy of Sciences and the Anhui Zhifei Longcom Biopharmaceutical.

Gao Fu, the head of China's Center for Disease Control, led the development of the protein subunit vaccine, which was approved by regulators last week for emergency use. It is the fourth vaccine to be given emergency use approval in China, three of which have since been approved for conditional market use.

Yan Jinghua, a key scientist behind the vaccine and a researcher from the CAS microbiology institute, said in a news briefing that the recombinant subunit vaccine works by training the body to recognize the spike protein of SARS-CoV-2, which is similar to many other COVID-19 vaccines.

The difference with the subunit protein vaccine is that scientists will need to grow a genetically modified version of the protein in cells and then purify it before turning it into a vaccine, Yan said.

One of the biggest advantages of the subunit vaccine is that it does not involve cultivating live viruses, so the production process is safe and easy to scale up, she said. Meanwhile, this type of vaccine can be stored at 2 to 8 C, making it easy for storage and transportation.

Yan said the vaccine can induce a relatively high level of neutralizing antibodies against COVID-19, though she did not disclose any details.

Phase III clinical trials of the vaccine were launched in China, Uzbekistan, Pakistan, Ecuador and Indonesia in November 2020, with 29,000 volunteers scheduled to be vaccinated. The vaccine completed phase I and II clinical trials in October 2020, and results showed there were no serious adverse reactions.