BEIJING, Oct. 20 (Xinhua) -- Studies have shown that the development of COVID-19 vaccines has not been affected by how the virus has mutated, a Chinese official said Tuesday.

China has paid close attention to the issue of virus mutation and has organized more than 30 research institutions nationwide to carry out relevant tracking research, said Tian Baoguo with the Ministry of Science and Technology at a news conference in Beijing.

According to Tian, there are nearly 150,000 genome sequences of novel coronavirus in the global database, covering more than 100 countries and regions.

Analysis on more than 80,000 high-quality genome sequences showed that the virus does not display much variation, that such variations fall within the normal range, and these have no substantial impact on vaccine development, he said.

At present, the antigen design of COVID-19 vaccines is mainly targeted at the S-protein of the virus, the sequence of which is relatively stable.

In addition, the mutations at individual sites of the existing S-protein have little effect on antigen structure and immunogenicity. Previous tests have proven that the vaccines currently being tested can effectively neutralize the mutated virus, he added.

The scientific research team will continue to follow the mutation of the virus and make timely judgments to provide early warning and scientific reference for vaccine research and development, Tian said.