In the race to develop the world’s first COVID-19 vaccine, Brazil – now one of the world’s worst-affected countries – is becoming an attractive clinical trial destination for biopharma companies that heading into phase III trials. Chinese firm Sinovac recently received regulatory approval to test its vaccine candidate in Brazil with support from research centre Instituto Butantan.


On 3 July 2020, a Chinese COVID-19 vaccine was given approval by Brazilian regulatory agency Anvisa to begin phase III clinical trials in Brazil. The vaccine, developed by Sinovac Life Sciences Co., Ltd., will be tested in human subjects in tandem with Instituto Butantan, a research centre in Sao Paulo. 


In the study, slated to begin later this month, 9,000 healthcare professionals will be recruited from 12 research centres across six Brazilian states. Conducting clinical trials in Brazil means that the country will get access to licensing of the drug once it has been approved for use. 


Sinovac has been working on its candidate, dubbed CoronaVac, since late January and is constructing a manufacturing plant capable of producing up to 100 million doses per year.  CoronaVac utilises inactivated whole virus to stimulate immune response by growing the live virus in cultures and therefore is more time-consuming to produce than other candidates. Most other companies are developing vaccines using DNA or RNA from the novel coronavirus. However, Sinovac’s candidate produced an immune response in more than 90 percent of the healthy volunteers in its phase II study in China. 


Testing CoronaVac’s efficacy in a phase III trial requires thousands of subjects in countries where the virus is still circulating. Since COVID-19 is relatively contained in China, it is difficult to recruit enough subjects, whereas Brazil presents a much higher rate of infection. Sinovac is not the only firm recruiting volunteers in the South American nation. Another potential vaccine being jointly developed by Oxford University and AstraZeneca, the world’s leading and most advanced candidate so far, will also run trials in Brazil.


CoronaVac is one of five COVID-19 vaccines developed by Chinese firms that have entered clinical trials. The most advanced of these Chinese vaccines is CanSinoBIO’s adenovirus-based recombinant vaccine, the first in the world to enter phase II trials.