But that makes it unlikely a vaccine will be available before the US election which President Trump has promised.
Brazil’s National Health Surveillance Agency (ANVISA) said on Wednesday that a volunteer in a clinical trial of the COVID-19 vaccine developed by AstraZeneca and Oxford University had died, but said the trial would continue.
It was not immediately clear whether the volunteer received the vaccine or the placebo.
The regulator said while testing of the vaccine would continue, it provided no further details about the volunteer’s death, citing the medical confidentiality of those involved in trials.
Oxford confirmed it would keep testing.
“Following careful assessment of this case in Brazil, there have been no concerns about safety of the clinical trial, and the independent review in addition to the Brazilian regulator have recommended that the trial should continue,” the British university said in a statement.
The Federal University of Sao Paulo, which is helping coordinate phase three clinical trials of the vaccine in Brazil, said separately that the volunteer was a Brazilian.
CNN Brasil reported that the volunteer was a 28-year-old man who lived in Rio de Janeiro and died from COVID-19 complications.
The Brazilian government already has plans to purchase the vaccine and produce it at its biomedical research centre Fiocruz in Rio de Janeiro, while a competing vaccine from China’s Sinovac is being tested by Sao Paulo state’s research centre, the Butantan Institute.
More than 155,000 people in Brazil have died from COVID-19, the second highest death toll in the world after the United States. Brazil has diagnosed nearly 5.3 million cases of the virus, the third highest in the world after the US and India.
The US suspended trials of the vaccine from AstraZeneca, which is based in the United Kingdom, after a patient in the UK trial reported serious illness, pending a review from the US Food and Drug Administration (FDA).
Sources told Reuters news agency on October 20 that the US trial could resume as early as this week, following the completion of the FDA review.
The FDA did not immediately respond to Al Jazeera’s request for comment on whether the death of the Brazilian volunteer would affect the resumption of the trial in the US.