The Chinese company Sinovac Biotech developed an experimental vaccine for SARS back in 2004. That disease went away after killing just 800 people, and the project was shelved. But it meant that when the new coronavirus, SARS-CoV-2, exploded in China last January, the company had a road map for what to do next. Four months later, it published evidence that it could protect monkeys against the disease using a simple vaccine made from killed virus.
By then, though, China had a different problem: not enough covid-19. Its draconian lockdown measures had quashed the virus at home so effectively that doctors couldn’t find patients to fully test their vaccine on. The US had plenty of infections, but tensions between the countries meant no Chinese vaccine for covid-19 will ever be tested on US soil.
So in June Sinovac struck a deal with a Brazilian vaccine center, the Butantan Institute in São