Brazil halting coronavirus vaccine CoronaVac trial surprises the world

Brazil's health regulator has halted clinical trials of the potential coronavirus vaccine CoronaVac, citing an “adverse, serious event.” The decision posted on Anvisa's website Monday night elicited immediate surprise from parties involved in producing the vaccine.

The potential vaccine is being developed by Chinese biopharmaceutical firm Sinovac and in Brazil would be mostly produced by Sao Paulo's state-run Butantan Institute. Sao Paulo state's government said in a statement it “regrets being informed by the press and not directly by Anvisa, as normally occurs in clinical trials of this nature.”

Butantan said in a statement that it was surprised by