The COVID-19 vaccines that have been marketed in China have a neutralizing effect on some mutated viruses, including the ones found in the UK and South Africa, according to Sinopharm and Sinovac.
Sinopharm has been testing the antiviral mutation ability of vaccines already on the market in China, such as the inactivated vaccine developed by Sinopharm, to study whether the mutation of the virus would alter the efficacy of the vaccine, said Zhang Yuntao, vice president and chief scientist of China National Biotec Group (CNBG), a Sinopharm subsidiary, at a press conference on Sunday.
Two inactivated vaccines from Sinopharm have been used in a crossover trial on the strains found in South Africa and the UK as well as more than 10 strains found in different regions in China, using the serum after the phase II and III clinical trials in China and overseas, he said.
The results showed that the neutralizing antibodies produced by the two inactivated vaccines neutralized these strains well.
He also noted that Sinopharm is conducting neutralization trial monitoring on the strains found in Brazil and Zimbabwe.
At the press conference, Gao Qiang, general manager of Sinovac, another producer of COVID-19 vaccines, said that Sinovac has also carried out studies on the protection of its CoronaVac vaccine against the variant strains found in various countries in cooperation with several research institutions.
Sinopharm carried out neutralization trials on the variant strains in 10 countries during the initial stage of the study and the results showed that the vaccine developed at the time was protective against the variant strains discovered in each country, Zhang said.
Sinovac also used the strain discovered in Wuhan and the newly mutated strains found in the UK and South Africa to conduct the neutralizing antibody detection of immune serum after vaccination in 2021, and test results showed that the seroconversion rate was 100 percent after a dose of vaccine against the strains found in Wuhan and the UK, and 97 percent against the strains discovered in South Africa. The overall antibody level between the strains discovered in Wuhan and the UK was basically the same, he said.
China has administered more than 100 million doses of COVID-19 vaccines as of Saturday, the National Health Commission announced at a press conference on Sunday. The country's global supply of COVID-19 vaccines also topped 100 million doses as of Friday.
The inactivated vaccine developed by Sinopharm has been used in 50 countries and regions around the world. Zhang said the population sample size and large scale fully demonstrate the broad spectrum effect of the inactivated vaccine.
CNBG has designed COVID-19 booster shots to effectively improve the durability of antibodies. The company said initial results show booster shots can improve the vaccine's efficacy against virus variants, Zhang said.