Boxes containing 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 that efficacy is much lower than initially announced.
The vaccine was only 50.4% effective in preventing symptomatic infections in the Brazilian trial, including data on ‘very mild’ cases, researchers said on Tuesday.
Last week, they said the vaccine, called CoronaVac, shows 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 information from the Chinese firm on efficiency rates before approving and buying supplies.
“These Phase III clinical trial results are sufficient to demonstrate the safety and efficacy of the CoronaVac vaccine worldwide,” Sinovac Biotech Chairman Yin Weidong told a news conference.
Different countries use vaccinations from the same group in their trials, but the countries do not have identical test protocols, he said.
Piece flour disclosures from Sinovac’s trials as well as those from studies of other Chinese vaccines have expressed concern that they are not subject to the same public scrutiny as the US and European alternatives.
The data from Brazil was announced just as Indonesia began its vaccination campaign, with President Joko Widodo as the first to be vaccinated with Sinovac’s CoronaVac.
Malaysia said on Wednesday that the acquisition would only proceed if the vaccine met the safety and efficacy standards of local regulators.
Pharmaniaga Bhd, Malaysia, on Tuesday signed an agreement with Sinovac to buy 14 million doses of CoronaVac and later manufacture it domestically.
Singapore, the only high-income country with which Sinovac has entered into an agreement, said it will go through official data when Sinovac announces it, rather than depending on the effectiveness reported so far, and then decide whether to approve it .
Thailand, which ordered 2 million doses of CoronaVac, said it was still on track to receive and administer the vaccine from next month, but added that it would ask for information directly from Sinovac.