China Approves Sinovac Vaccine for Broad Use Against Covid-19

It is the second vaccine to receive approval for mass inoculation in China, following that of state-owned China National Pharmaceutical Group Co., more commonly known as Sinopharm, which was approved in December. Last June, CoronaVac received emergency-use authorization in China, limiting it to use within certain groups of high-risk individuals.

From Latin America to Africa and Asia, many developing countries have pinned their hopes on CoronaVac and other Chinese vaccine candidates as richer nations snap up inoculations developed in the West. CoronaVac can be stored in an ordinary refrigerator, making it cheaper and easier to transport than others that require subzero storage temperatures.

Beyond mainland China and Hong Kong, Turkey and Ukraine are among nations that have reported orders for CoronaVac. Brazil has agreed to buy up to 100 million doses, while Turkey has purchased 50 million shots.

But CoronaVac has also faced increasing scrutiny over its effectiveness, after the drug was found to have a lower efficacy than originally published during late-stage trials in Brazil—dropping from 78% to around 50%—following pressure from local scientists for the trial’s organizers to release more data.

Varying numbers from other countries conducting CoronaVac trials have also raised questions around the protection offered by Sinovac’s vaccine. In December, researchers in Turkey said the drug was just over 91% effective, whereas Indonesian authorities in January reported an efficacy rate of 65.3% from preliminary results of clinical trials.

Sinovac’s chairman has said that results from Turkey, Indonesia and Brazil have proven the vaccine was sufficiently safe and effective.

According to the company, which published details on CoronaVac tests in a statement Saturday, clinical trials in Brazil showed that the vaccine offered total protection against severe and deadly cases of the coronavirus. Efficacy dropped to 83.7% for patients who contracted less serious cases that still required medical intervention, the company said. For even milder cases, efficacy was about 50.7%.

In Turkey, clinical trials showed that CoronaVac was about 91.3% effective, according to Sinovac, without detailing numbers by case severity. More than 25,000 people outside China have participated in CoronaVac clinical trials, it said.

Earlier this week, the scientific journal The Lancet published new figures on CoronaVac tests conducted on hundreds of people aged 60 and above in China, since trials in Turkey, Brazil and Indonesia didn’t include elderly participants.

It showed the vaccine was safe to use and that it induced antibodies in participants. That suggests it will be effective for the older age group, although Sinovac would need to conduct Phase 3 trials on a greater number of people, and likely outside of China where the virus is still spreading.

Vaccines by Sinopharm and Sinovac are currently approved for use in China only for those 59 years old and below. Chinese authorities have said they would inoculate the elderly, although they haven’t said when. The state-run Global Times newspaper reported that the results of the early study paved the way for approval and expansion of the Sinovac vaccine in the elderly group.

The Chinese government, which has actively promoted the country’s vaccines overseas, is also donating shots to less affluent countries, such as Zimbabwe, which will receive 200,000 doses of Sinopharm’s vaccine, according to Chinese state media. Beijing will also give 10 million coronavirus vaccines through the Covax initiative, the main global effort to provide vaccines to poor countries.

—Raffaele Huang and Chao Deng contributed to this article.

Write to Eva Xiao at eva.xiao@wsj.com