Brazil pauses COVID-19 vaccine trial after volunteer dies

Nov. 10 (UPI) -- Brazilian officials say they have paused a late-phase trial for a COVID-19 vaccine being developed by China after one of the human test subjects died.

Anvisa, Brazil's national health surveillance agency, said the "severe adverse event" occurred late last month, but didn't specify the circumstances of the volunteer's death.

Chinese firm Sinovac has been performing the late-stage trial for the potential vaccine, called CoronaVac, in collaboration with the Brazilian Butantan Institute in Sao Paulo.

"The agency decided to suspend the study to evaluate the data observed so far and judge the risk and benefit of continuing the study," Sinovac said Monday.

The company said the volunteer's death was not related to the clinical trial.

"We learned the head of Butantan Institute believed that this serious adverse event is not related to the vaccine," Sinovac said in a statement.

"We are confident in the safety of the vaccine."

"It's a death unrelated to the vaccine because there are more than 10,000 volunteers right now, the person can have a traffic accident and die," added Butantan Institute Director Dimas Covas.

"This never leads to the interruption of a clinical trial. I ask now that ... these details get clarified."

There are dozens of potential coronavirus vaccines presently in development worldwide. Pfizer said Monday that early data for its final-stage candidate so far indicate that it is about 90% effective.