The coronavirus disease (COVID-19) aroused since the end of 2019 has drawn worldwide attention, and its causative agent has been identified as a novel coronavirus designated as SARS-CoV-2. The global confirmed cases have exceeded 160 million, with the death toll reaching 600,000. Hence, there is an urgent need for the development of an effective vaccine to prevent the virus infection and to counteract the current pandemic. To set up infection, SARS-CoV-2 needs to first use its spike protein receptor binding domain (S-RBD) to engage the host receptor of angiotensin converting enzyme 2 (ACE2). This receptor-binding process is one of the most crucial steps in SARS-CoV-2 infection.

On July 29, a research paper entitled A vaccine targeting the RBD of the S protein of SARS-CoV-2 induces protective immunity was published online in Nature. This is thus-far the first research paper on COVID-19 vaccine published in Nature. It was found that the recombinant S-RBD vaccine can induce effective antibody response in immunized mice, rabbits and non-human primate (macaque) as early as 7 or 14 days after a single dose injection, and that the immunized serum can block RBD to ACE2 expressed on the cell surface and neutralize the infection with both the SARS-CoV-2 pseudovirus and the live SARS-CoV-2 virus in vitro. Importantly, the vaccine has also been shown to provide protection in non-human primates to live SARS-CoV-2 challenge in vivo. In addition, no evidence of antibody-dependent enhancement or acceleration of pneumonia was observed in immunized animals. Therefore, the recombinant RBD protein vaccine represents a good candidate for the development of a protective vaccine against SARS-CoV-2.

This team is actively devoted to the clinical test of this vaccine and its industrialization at Chengdu High-tech Industrial Development Zone, and is designing the production line with the capacity of up to 100 million doses per year. During the R&D of the vaccine, the team has acquired strong supports from the Ministry of Science and Technology, the National Health Commission and the Ministry of Education, as well as some provincial and municipal departments. In addition, a couple of other scientific research institutions have also participated in the project.