The Covid-19 vaccine developed by Sinovac Biotech China is said to be only 50.4% effective in Brazilian trials, barely meeting the criteria required for regulatory approval and well below the previously reported effectiveness rate.
Brazil is the first to complete the Covid-19 vaccine final stage trial. The Butantan Institute, which is run by the country, has previously been criticized by scientists and health experts for its lack of transparency in announcing its test data.
The institution has reportedly delayed the test results three times, which they blamed on clauses in its contract with Sinovac.
Even last week they announced some data showing an effectiveness rate of 78%. However, this week, the results published by the institution differed with only 50.4% effectiveness recorded.
In comparison, the Covid-19 vaccine developed by Pfizer-BioNTech and Moderna was found to have about 95% effectiveness in their final testing.
Apart from Brazil, other developing countries including Turkey and Indonesia are also testing the Sinovac vaccine also known as CoronaVac.
On Monday, Indonesia became the first country outside China to approve a vaccine for emergency use after temporary data from a final-stage trial showed that CoronaVac was effective 65.3%.
