Brazil’s Butantan Institute has found the CoronaVac, a COVID-19 vaccine developed by China’s Sinovac Biotech, to be only 50.4% effective, according to CNBC. The efficacy rate is below the earlier reported 78% and barely meets the threshold for regulatory approval. 

  • Brazilian state-run Butantan Institute has been criticized by health experts and scientists for lack of transparency in making public its trial data.
  • Butantan institute reportedly delayed releasing trial results three times, blaming it on a confidentiality clause in its contract with Sinovac.
  • Brazil is the first to complete a late-stage trial of the vaccine CoronaVac and last week announced partial data that showed an efficacy rate that was later revised lower.
  • Brazil and other developing nations have pinned their hopes on Chinese vaccines as wealthier countries snap up vaccines developed in the West. 
  • Sinovac’s CoronaVac vaccine is also cheaper and easier to transport because it can be stored in ordinary refrigerators.
  • Butantan has requested for CoronaVac to be authorized for emergency use with the health regulator stipulating a minimum of 50% efficacy rate.

Sinovac’s stock is currently declining.  SVA: NASDAQ is down 0.31% on premarket