Trials of a coronavirus vaccine being developed by Oxford University will continue following a review of the death of a volunteer.
The university is in advanced stages of testing a Covid-19 immunisation being developed with AstraZeneca, with volunteers in countries including Brazil, the UK and the US.
The institution said it has investigated the case but found "no concerns about safety" around the vaccine.
Oxford said in a statement: "All significant medical incidents, whether participants are in the control group or the Covid-19 vaccine group, are independently reviewed.
"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."
Brazil's health authority said it was informed of the death of a participant earlier this week.
AstraZeneca said it could not comment on individual cases due to patient confidentiality, but said all due processes had been followed and there were no issues with the trial continuing.
A spokesperson said: "All significant medical events are carefully assessed by trial investigators, an independent safety monitoring committee and the regulatory authorities.
"These assessments have not led to any concerns about continuation of the ongoing study."
According to local media reports, the volunteer had been given a placebo jab rather than the vaccine.
