Brazilian health authority Anvisa says a volunteer in a clinical trial of the COVID-19 vaccine developed by AstraZeneca and Oxford University has died but adds that the trial will continue.
Oxford confirmed the plan to keep testing, saying in a statement that after careful assessment “there have been no concerns about safety of the clinical trial”.
Brazilian newspaper O Globo reported that the volunteer had been given a placebo and not the trial vaccine, citing unnamed sources.
Anvisa provided no further details, citing medical confidentiality of those involved in trials.
But it has been reported elsewhere that he died of complications due to COVID-19.
AstraZeneca declined immediate comment.
The Federal University of Sao Paulo, which is helping coordinate phase three clinical trials of the vaccine in Brazil, separately said the volunteer was Brazilian without revealing where the person lived.
AstraZeneca shares fell 1.7 per cent.
Trials of the AstraZeneca vaccine were put on hold in September after a participant experienced a serious adverse reaction. They restarted several days later, although they remain on hold in the US.
The Morrison government has signed a deal to buy millions of doses of the AstraZeneca drug, if it is approved for widespread use.
The Brazilian government also has plans to purchase the British vaccine and produce it at its biomedical research centre FioCruz in Rio de Janeiro. A competing vaccine from China’s Sinovac Biotech is also being tested by Sao Paulo state’s research centre Butantan Institute.
Brazil has the second deadliest outbreak of coronavirus, with more than 154,000 killed by COVID-19, following the US.
It has the third largest number of cases, with more than 5.2 million infected, after the United States and India.