Boxes of Sinovac Biotech’s CoronaVac SARS-CoV-2 vaccine will be unveiled at a media event in Beijing, China, on Thursday, September 24, 2020.
Nicolas 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 released late-stage clinical data showing efficiencies much lower than originally announced.
The vaccine was only 50.4% effective in preventing symptomatic infections in the Brazilian trial, including data on “very mild”
Last week, they said the vaccine, called CoronaVac, showed 78% efficacy against “mild to severe” cases.
The news prompted Malaysia and Singapore, which have purchase agreements with Sinovac, to say on Wednesday that they would seek more data from the Chinese company on efficiency levels before approving and purchasing supplies.
“These Phase III clinical results are sufficient to demonstrate the safety and efficacy of CoronaVac vaccines worldwide,” said Sinovac Biotech President Yin Weidong at a news conference.
Different countries used vaccines from the same batch in their trials, but the countries do not have identical test protocols, he said.
Partial revelations from Sinovac’s trials, as well as from studies of other Chinese vaccines, have raised concerns that they are not subject to the same official controls as American and European alternatives.
The data from Brazil was released just as Indonesia rolled out its vaccination campaign, with President Joko Widodo being the first to be grafted with Sinovac’s CoronaVac.
Malaysia said on Wednesday that it would only proceed with procurement if the vaccine met the safety and efficacy standards of local regulators.
On Tuesday, Malaysia’s Pharmaniaga Bhd signed an agreement with Sinovac to buy 14 million doses of CoronaVac and later manufacture it domestically.
Singapore, the only high-income nation with which Sinovac has entered into an agreement, said it would review official data when Sinovac releases it, rather than depending on its effectiveness 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 from next month, but added it would ask for information directly from Sinovac.