People wait to receive the Sinopharm COVID-19 vaccine in Colombo, Sri Lanka, on Aug. 7, 2021.(Photo: Xinhua)

Chinese vaccine producer Sinopharm's inactivated COVID-19 vaccine does not increase the risk of thrombosis or thrombocytopenia in recipients and the latest real world data form Argentina shows that the vaccine has an 84 percent death-protection efficacy among people aged 60 and above, according to a statement from China National Biotec Group (CNBG), a subsidiary of Sinopharm. 

The seroconversion rate of SARS-CoV-2 specific antibodies was 95.81 percent four weeks after vaccination with a shot developed by CNBG, Sinopharm said in a statement on Monday, citing a study published on July 27 in the Science Bulletin journal.

None of the subjects had spontaneous thrombosis or thrombocytopenia over a minimum follow-up period of eight weeks and there were no changes in autoantibody profile or unfavorable clinical manifestations, according to the article. 

The study was conducted on 406 healthcare workers who received two doses, 21 days apart, in Shanghai Ruijin Hospital. They were recruited from January 14 to March 10, 2021, with a minimum follow-up period of eight weeks. 

Rare but severe side effects characterized by dangerous blood clots and low platelet counts after administration of the adenovirus-vectored COVID-19 vaccine have been reported globally and have attracted a lot of attention, so Chinese researchers conducted this study to explore whether the CNBG COVID-19 vaccine could lead to similar problems. 

Some recipients of the Oxford/AstraZeneca adenovirus vector COVID-19 vaccine have reportedly suffered blood clots after the vaccine was rolled out in the UK in January. 

The World Health Organization's advisory vaccine safety panel said in April that a causal link between the AstraZeneca COVID-19 vaccine and rare cases of blood clots with low platelets is "considered plausible but is not confirmed."  

In a recent study, researchers from the Massachusetts Medical Society identified 170 definite and 50 probable cases of the rare clotting - who presented to UK hospitals between March 22 and June 6 - as vaccine-induced immune thrombocytopenia and thrombosis, media reports said.

Sinopharm has developed two inactivated COVID-19 vaccines, one by its institute in Beijing and the other by another institute in Wuhan. 

The vaccines have been approved for emergency use in 98 countries and regions and have been recognized by international organizations including the World Health Organization, CNBG said.   

According to another statement from CNBG on Tuesday, the vaccines have demonstrated an overall death-protection rate of 84 percent in people aged 60 and above in Argentina, based on data for nearly 150,000 people. 

The rate was 80.2 percent in the 60-69 age group, 88.3 percent in those aged 70-79 and 77.6 percent in those aged 80 and above.  

CNBG said that the first shot can provide a death-protection efficacy of 61.6 percent for people aged 60 and above. Also, only 1,866 side effect cases were reported after more than four million CNBG shots had been given, CNBG noted.

Global Times