Boxes of Sinovac Biotech’s CoronaVac SARS-CoV-2 vaccine were unveiled at a media event in Beijing, China, on Thursday, September 24, 2020.
Nicola Bock Bloomberg | Getty images
China’s Sinovac Biotech defended the safety and efficacy of its experimental Covid-19 vaccine on Wednesday after researchers in Brazil published clinical data in the final stage showing efficacy that was much lower than originally announced.
The vaccine was only 50.4% effective in preventing symptomatic infections in the Brazilian study, including data on “very mild”
Last week, they said the vaccine, called CoronaVac, had shown 78% effectiveness against “mild to severe” cases.
The news prompted Malaysia and Singapore, which have purchase agreements with Sinovac, to say on Wednesday that they would ask the Chinese company for more data on efficiency levels before approving and purchasing supplies.
“These results of phase III clinical trials are sufficient to prove that the safety and efficacy of CoronaVac vaccine are good worldwide,” Sinovac Biotech chairman Yin Weidong told a news conference.
Different countries have used vaccines from the same batch in their experiments, but the countries do not have identical testing protocols, he said.
The revelations of pieces from Sinovac’s experiments, as well as those from studies of other Chinese vaccines, have raised concerns that they are not subject to the same public scrutiny as alternatives to the United States and Europe.
The data from Brazil was published just as Indonesia began its vaccination campaign, with President Joko Vidodo being the first to be inoculated with Sinovac’s CoronaVac.
Malaysia said on Wednesday it would resume deliveries only if the vaccine meets safety and efficacy standards from local regulators.
On Tuesday, Malaysian Pharmaniaga Bhd signed a deal with Sinovac to buy 14 million doses of CoronaVac and later produce it domestically.
Singapore, the only high-income country with which Sinovac has struck a deal, said it would go through official data when Sinovac released it, instead of depending on the efficiency reported so far, and then decide whether to approve it.
Thailand, which has ordered 2 million doses of CoronaVac, said it was still on track to receive and administer the vaccine next month, but added that it would request information directly from Sinovac.