The Chinese Sinovac vaccine has been shown to be 78% effective against Covid-19 in late Brazilian studies and provides total protection against severe cases of the disease, raising the hope that it can be used to immunize much of the developing world.
Brazil’s Butantan Institute, the São Paulo-based research center that tested CoronaVac in phase 3 studies, said on Thursday that none of the volunteers who took the vaccine developed serious cases of Covid-19. More than 12,000 health professionals participated in phase 3 studies in Brazil, the first country to complete tests of the Sinovac vaccine.
“It’s a great result,” said Luiz Carlos Dias, part of a Covid-19 task force of researchers at the University of Campinas, São Paulo state. “If it can prevent serious cases, hospitalizations and deaths, it will help us get out of this pandemic.”
The CoronaVac vaccine is less effective than the vaccine developed by Moderna Inc. and jointly by Pfizer Inc. and BioNTech SE, which have been shown to have an efficacy of 94.5% and 95% respectively when tested. But CoronaVac can be stored in a standard refrigerator between about 36 and 46 degrees Fahrenheit, making it easier and cheaper to transport and store in less developed countries, infectious-disease specialists say.
Prashant Yadav, a global health specialist at the Center for Global Development think tank in Washington, said 78% is high enough for many developing countries to consider using the vaccine and possibly good enough for the World Health Organization to consider including CoronaVac in its global distribution system.