Sinovac vaccine 78% effective in trial in Brazil, experts ask for more details

SAO PAULO (Reuters) – A coronavirus vaccine developed by China’s Sinovac Biotech was 78% effective in a Brazilian trial at an advanced stage, without serious cases of COVID-19, the researchers said on Thursday, although the lack of details of the generated requests for more transparency.

The test results, observed closely by developing countries that rely on the vaccine to begin mass inoculation to help end a violent pandemic, were below preliminary findings by Turkish researchers and lacked detailed data provided on American vaccines and European

The director of the Butantan Biomedical Center, Sinovac’s research and production partner, said the detailed results are being forwarded to the health regulatory agency Anvisa as part of an emergency use order for the vaccine.

“One thing is a presentation at a press conference. Another thing is to take the data and analyze it, which is what Anvisa will do ”, said Cristina Bonorino, who is part of the scientific committee of the Brazilian Society of Immunology. “If that’s what they say, it’s an excellent result,” he added.

Brazil and Indonesia, which have the highest number of COVID-19 cases in Latin America and Southeast Asia, respectively, are preparing to launch the vaccine, called CoronaVac, this month. Turkey, Chile, Singapore, Ukraine and Thailand have also entered into supply agreements with Sinovac.

Although CoronaVac’s effectiveness falls short of the 95% success rate of vaccines from Moderna Inc or Pfizer Inc with partner BioNTech SE, it is easier to transport and can be stored at normal refrigerator temperatures.

The 78% effectiveness rate is also well above the 50% to 60% benchmark set by global health authorities for vaccines developing at the start of the pandemic, given the urgent need.

Moderna and Pfizer / BioNTech released detailed results of final-stage tests last year, before receiving emergency use permits in the United States and elsewhere.

Butantan’s director, Dimas Covas, told a news conference that the full CoronaVac data would be released in an unspecified scientific publication, but did not provide a timeline.

Pressed by journalists, Covas said there were 218 cases of COVID-19 in the trial of 13,000 volunteers. Just over 160 of these cases occurred among participants who received a placebo and the rest were in vaccinated volunteers, he said.

Unlike other vaccine studies, the CoronaVac do Brasil trial included elderly volunteers, a particularly vulnerable population.

Covas said CoronaVac totally prevented serious cases of COVID-19 among the vaccinated group, including the elderly. None of those who received the vaccine became ill enough to require hospitalization, he added.

SOME DETAILS

The gradual disclosure of the results of CoronaVac’s global studies raised concerns about the transparency of the tests, which was not helped by the Butantan press conference.

“It was not clear or transparent,” said Denise Garrett, an epidemiologist who has worked for 23 years at the Centers for Disease Control and Prevention (CDC) in the United States. “They showed secondary outcomes in preventing mild, severe cases and hospitalizations, but not the effectiveness in preventing diseases.”

The partial disclosure of Butantan, which postponed its announcement three times, citing obligations to Sinovac, increased skepticism about the Chinese vaccine in Brazil. Nearly half of Brazilians said they would not get a COVID-19 vaccine developed by China, according to a December survey.

Brazilian President Jair Bolsonaro expressed disdain for the Sinovac vaccine, citing doubts about its “origin”. He traded barbs with political rival João Doria, the governor of São Paulo, who finances the trials and shooting.

Still, Health Minister Eduardo Pazuello said on Thursday that the federal government would buy Butantan’s full CoronaVac production this year, close to an agreement to buy 100 million doses for a national immunization program.

Brazil has the second most deadly outbreak in the world, after the United States, with a death toll that surpassed 200,000 on Thursday, and plans to vaccinate 51 million people, or about a quarter of its population, in the first half of 2021. [nL1N2JI32B]

Immunizations have not yet started. Doria reiterated that São Paulo, the richest and most populous state in the country, should start vaccination on January 25.

Based on traditional vaccine technology using inactivated coronavirus to trigger an immune response, CoronaVac can be stored at temperatures from 2 to 8 degrees Celsius (36 ° -46 ° F) and can remain stable for up to three years.

The vaccines offered by Pfizer / BioNTech and Moderna use a new synthetic messenger RNA (mRNA) technology, requiring much colder temperatures for transport and storage. The Pfizer / BioNTech vaccine must be kept at a subarctic temperature, making it an ineffective option for poor nations and areas without the necessary refrigerated storage equipment.