China’s CoronaVac shows only 50.4 percent efficacy in late-phase studies taking place in Brazil – much lower than previous projections and barely enough to gain regulatory approval.
The new data, reported by researchers on Tuesday, is a major blow to the South American country as it weathering a second wave of one of the largest COVID-19 outbreaks in the world.
The Beijing-made vaccination of Sinovac is just one of two vaccines approved for trials by Brazilian authorities, the outlet reported.
Last week, researchers in Brazil celebrated results showing a much higher efficacy rate of 78 percent against ‘mild to severe’ COVID-19 cases, but did not disclose that there was a group of people who received the vaccine and still developed ‘very mild’ . infections.
The latest data includes that group, according to Richard Palacios, medical director for clinical research at the Butantan Biomedical Center in Sao Paulo.
Palacios and government officials insisted the data was still good news as none of the volunteers required hospitalization – so even if the vaccine is effective only 50 percent of the time, the cases are mild and will leave the country’s overburdened hospitals. do not burden further.
“It is a vaccine that will start the process of overcoming the pandemic,” microbiologist Natalia Pasternak told Reuters.
‘We have a good vaccine. Not the best vaccine in the world. Not the ideal vaccine, ”the scientist said, criticizing Butantan’s triumphant tone.
Butantan officials also argued that the design of the Brazilian study – which targeted primary health care workers and older volunteers – made it impossible to compare with other studies taking place outside the country.
Turkish researchers found last month that Beijing’s vaccination was 91.25 percent effective, and Indonesia granted emergency permission for the vaccine on Monday, when interim data showed it to be 65 percent effective.
The shots from Pfizer and Moderna, both approved for emergency use in the US, were each found to be 95 percent effective at warding off COVID-19 in their pivotal Phase 4 studies.
Brazil’s national immunization program uses CoronaVac, along with the shot made by Oxford University and AstraZeneca. Neither is approved for use.
With pole wires