CoronaVac: What we know about China’s Covid-19 vaccine and questions unanswered

CoronaVac: As Covid-19 vaccines are making breakthrough across the globe with their success stories, China too is leaping with bounds and colours with its Covid-19 vaccine front-runner, CoronaVac. The vaccine, being developed by China’s Beijing-based pharma giant, Sinovac, has already arrived in Indonesia for country’s mass vaccination drive against Coronavirus. Another shipment of additional 1.8 million doses is scheduled for January. But the big question of what we truly know about this vaccine arises from the fact that Sinovac vaccine is yet to finish its last phase of trials. 

Chemistry around Sinovac vaccine & how it’s different from other Covid-19 vaccines 

Sinovac’s CoronaVac is an inactivated vaccine, which means it contains killed viral particles which trigger immune response in body when inoculated. The chances of this type of vaccine to risk a serious response are negligible. In contrast, Pfizer and Moderna have developed mRNA vaccines, that is, part of the viral genetic code is injected that triggers body to produce viral proteins, but not the complete virus. This triggers immune response in body. But mRNA vaccines can trigger an adverse response. 

Associate Prof Luo Dahai of the Nanyang Technological University explains, “CoronaVac is a more traditional method of vaccine that is successfully used in many well known vaccines like rabies. mRNA vaccines are a new type of vaccine and there is currently no successful example of them being used in the population.” 

Furthermore, CoronaVac requires standard refrigerator temperature of 2-8C for storage. Oxford vaccine too requires similar temperatures. But Moderna and Pfizer vaccines require extremely low temperatures of -20C and -70C respectively. This makes CoronaVac and Oxford vaccines perfectly suitable for developing nations. 

What do we know about its efficacy?

As we only have data of first and second phase of trials of the vaccine, the exact efficacy of CoronaVac is difficult to determine, according to scientific journal The Lancet. The first phase trials included 144 participants while second phase had 600 volunteers. This means the vaccine is suitable for emergency use. In September, Sinovac relayed that after tests were done on 1000 people, just under 5% displayed minor fatigue or discomfort. 

Sinovac’s Brazilian partner, The Butantan Institute expects the trials results to be published by Sinovac before December 15. Late stage trials of CoronaVac were started in Brazil in November. 

How many CoronaVac doses can be produced in a year?

China’s pharma giant Sinovac will be able to manufacture 300 million doses of vaccine in a year in its newly built production plant sprawling across 20,000 sqm. But it, like other vaccines, requires two doses per person. This means 150 million people will be able to receive vaccination. 

Sinovac has already dispatched a vaccine lot to Indonesia, and has secured deals with Brazil, Turkey and Chile. 

After being centre of criticism of all nations due to coronavirus infection spread, China is now desperate to rise and shine with its bid to win vaccine race. President Xi Jinping has pledged $2 billion for Africa and has also offered a loan of $1 billion to Latin America and Caribbean nations for buying vaccines. But keeping in mind China’s track record, it is expected that these deals might have a hidden agenda or catch with a clause for some diplomatic or commercial profit in exchange.