China’s Sinovac vaccine has been shown to be 78% effective against Covid-19 in late-stage studies in Brazil and provides complete protection against severe disease, raising hopes that it can be used to immunize many developing countries.
The Butantan Institute in Brazil, the research center in São Paulo, which tested CoronaVac in phase 3 studies, said on Thursday that none of the volunteers who received the vaccine developed severe cases of Covid-19. More than 12,000 health workers took part in Phase 3 studies in Brazil, the first country to complete Sinovac vaccine tests.
“It’s an extraordinary result,” said Luiz Carlos Dias, part of a Covid-19 group of researchers at the University of Campinas in São Paulo. “If it can prevent serious cases, hospitalizations, deaths, it will help us get out of this pandemic.”
The CoronaVac vaccine is less effective than those developed by Moderna Inc. and jointly by Pfizer Inc. and BioNTech SE which have been shown to have efficacy rates of 94.5% and 95% respectively in testing. But CoronaVac can be stored in a standard refrigerator between 36 and 46 degrees Fahrenheit, making it easier and cheaper to transport and store in less developed countries, said infectious disease specialists.
Prashant Yadav, a health specialist at the Center for Global Development in Washington, said 78% is a high enough rate for many developing countries to consider vaccine use and potentially good enough for the World Health Organization to consider incorporating CoronaVac into the global distribution system.