Brazil’s Anvisa Gets Around to Emergency Authorization After Some Confusion Involving CoronaVac Efficacy Rates

Brazil’s Anvisa Gets Around to Emergency Authorization After Some Confusion Involving CoronaVac Efficacy Rates TrialsiteN

After much confusion, especially with the Sinovac vaccine results, The Brazilian National Health Surveillance Agency (Anvisa) approved the emergency use of both a vaccine developed out of China called CoronaVac as well as AZD1222, developed originally by University of Oxford and taken on and commercialized by AstraZeneca. Most of the hardest hit by the COVID-19 pandemic, Brazil has registered 8.5 million infections and 209,000 deaths, now the government of Sao Paulo administered the first dose of CoronaVac, developed by Sinovac.

Recently reported by EuroWeekly, the first person to receive the jab (outside of a clinical trial) from the CoronaVac vaccine was a nurse named Monica Calazans, based in the East Zone of the region in a community known as Itaquera. A frontline health care worker, she is deemed high risk and given literally the front of the line. She was also a volunteer, as it turns out, in the Phase 3 clinical trial investigating CoronaVac—it turned out, she received a placebo. After the administration of the vaccine, governor Joãra Doria gave her a stamp with the words, “I am vaccinated by Butantan” as well as a bracelet inscribed with the quote, “I vaccinated myself.” Ms. Calazans was followed by another nurse named Wilson Paes de Pádua from the Vila Penteado hospital.

Shipment from India Sought

Recently, Brazil’s state-run Fiocruz Institute (also known as the Oswaldo Cruz Foundation) recently sought an emergency use authorization for the AstraZeneca COVID-19 vaccine. It plans on importing the product from AstraZeneca’s partner in India, the Serum Institute of India, the world’s biggest vaccine producer as measured by volume. A well known public health research institute, they seek 2 million doses.

Government Makes the Move

And just a couple days ago, CNN reported that the health officials from Anvisa finally got around to authorizing the two vaccines, one of course from AstraZeneca (Oxford) and the other Coronavac. And this occurred just in time as the second wave of the COVID-19 pandemic stresses health systems. Brazil has the third highest number of total COVID-19 cases followed by Russia and the United States. With over 8 million cases and 200,000 deaths, Brazil has moved slower to authorize vaccines despite its notable prominent public health and vaccination infrastructure.

CoronaVac Efficacy

Developed by Sinovac in China, Coronavac has a varied track record. What follows is a table aggregate efficacy data from various clinical trials.

CoronaVac Efficacy

BrazilPhase 3, 13,000 participantsOverall efficacy 50.38%
TurkeyPhase 3 interim analysis of 29 cases, based data from 1,322 participants in trial with 7,371 total volunteers91.25%
IndonesiaPhase 3, interim analysis of 25 cases; based on data of 1,600 participants65.3%


While various efficacy rates have been reported, the overall average Sinovac efficacy rate of 50.4% was due, according to Ricardo Palacios, Medical Director of Instituto Butantan, to higher standards for what is measured as an infection among study participants. Including six types of cases in the study results, including asymptomatic, very mild, mild, two levels of moderate and severe; this differed from most western vaccine developers who focused on three categories of mild, moderate, and severe. One expert suggested the low efficacy rate was due to the fact that most of the Brazilian subjects were front line healthcare workers, which intensified their exposure to the pathogen.