CanSinoBIO's vaccine Photo: VCG

Chinese vaccine producers are accelerating researches and making major progresses in updating current vaccines for coronavirus variants and Sinovac said they would apply for clinical trials and emergency use for new vaccines against Gamma and Delta in near future.

China's Sinovac will submit an application in several countries for clinical research and emergency use on vaccines targeting the Gamma and Delta variants, Sinovac CEO, Yin Weidong, said on Thursday during a forum on international cooperation on COVID-19 vaccines hosted by Chinese State Councilor and Foreign Minister Wang Yi. 

The Global Times learned that the vaccines mentioned by Yin would be new products, different from the CoronaVac shot currently available in the market, and are especially designed for specific variants. The new products, if successfully developed and approved in other countries, would be supplied depending on the dominating local variant.

Recently, a new round of epidemic flare-up occurred in China caused by the Delta variant, which spread to many provinces and cities, causing concerns over the urgency of China to update its vaccines to deal with the variant and the need for booster shots. 

Yin noted at Thursday's forum that Sinovac is able to produce different kinds of vaccines targeting different variants. Sinovac has also finished research on booster shots of CoronaVac, which shows that booster shots can quickly increase the level of neutralizing antibodies within one week. The results would soon be published on Science.?

Sinovac is not the only Chinese vaccine producers that is studying booster shots. A booster shot six months after the dose of CanSinoBIO's vaccine increased the level of neutralizing antibodies by about 8 times, the latest lab study shows, Zhu Tao, cofounder and Chief Scientific Officer of CanSinoBIO, announced in a forum on Thursday.

According to the results of neutralizing antibody cross tests, CanSinoBIO's vaccine has a protective effect against Delta and other variants.

According to a recent paper published by the China National Institute of Food and Drug Control, CanSinoBIO's adenovirus vector vaccine can bring similar levels of neutralizing antibody against 9 different strains with a slight decrease in efficacy against the Beta variant first discovered in South Africa.

Its neutralizing ability against the Delta variant was about 0.9 to1.4 times lower than for the D614G strain which is prevalent in the United Kingdom. The neutralization effect of inactivated vaccines on the Delta variant was about 1.4 to 2.3 times lower than for the D614G strain.

The Global Times also learned from CanSinoBIO that it is updating its vaccine for variants of the virus. The company said that if they discover a variant that can break through the current vaccine, they are able to develop a new product targeting that mutation.

Among the four vaccines that have been approved for emergency use in China,  CanSinoBIO's shot is the only COVID-19 vaccine that requires a single dose. 

Zhu said that recipients of the vaccine show a high level of neutralizing antibodies in six months after vaccination and the level of neutralizing antibodies would increase by eight times if a booster shot is administered six months following vaccination. 

According to media reports, research fellows in East China's Jiangsu Province found that the level of antibodies of recipients would climb by times if they take a CanSinoBIO booster shot after two doses of inactivated vaccines. 

Chinese authorities and producers have been accelerating research and development of vaccines to deal with the rapidly mutating virus as the world is dragged into a new wave of the COVID-19 pandemic caused by the rampaging Delta variant, which is much more infectious than the original virus. 

Sources told the Global Times that Chinese authorities and experts are discussing the need of providing booster shots and updating Chinese vaccines to target the Delta variant. 

A Beijing-based immunologist told the Global Times that it will take some time to conduct research and update vaccines for mutations.

It is possible that Chinese authorities would provide booster shots to domestic residents before updated vaccines are available, the expert said.

Chinese companies have also announced that their COVID-19 vaccines are still effective in protecting recipients from various mutations of the virus, including the Delta variant.   

The Global Times learned on Wednesday that the COVID-19 vaccine produced by Shenzhen Kangtai Biological Products Co Ltd can protect against different variants of the novel coronavirus, including the increasingly dominant Delta variant. The company said it had recently succeeded in isolating the Delta strain and would continue to evaluate it for further vaccine development.

Yang Xiaoming, Chairman of Sinopharm China National Biotec Group, a Sinopharm subsidiary, told the Global Times on Thursday that the company is conducting neutralization tests on the Delta variant with the serum of vaccine recipients and is ramping up the development of vaccines targeting the four dominant variants: Alpha, Beta, Gamma and Delta.

Yang Guang, Chief Business Officer of Sinovac Biotech Ltd and General Manager of Sinovac Biotech (Hong Kong) Ltd, also informed the Global Times that they are conducting tests on the Delta variant to develop special vaccines.