The Brazilian Health Agency Anvisa disclosed yesterday that a volunteer in AstraZeneca’s (AZ) COVID-19 vaccine trial has died, with later reports adding that the death occurred in the placebo arm.
Anvisa confirmed that the trials of the COVID-19 vaccine would continue after the volunteer death, although it disclosed no additional information due to confidentiality protocols.
According to Reuters, a source familiar with the matter said the trial would have been paused if the participant had received the COVID-19 vaccine, implying that the death occurred in the placebo arm of the study.
While half of the trial population will have received the Oxford University-partnered vaccine candidate, the rest of the volunteers – known as the placebo group – are given an existing meningitis vaccine.
In a statement, a spokesman for Oxford University told Reuters: “Following careful assessment of this case in Brazil, there have been no concerns about the safety of the clinical trial, and the independent review in addition to the Brazilian regulator have recommended that the trial should continue.”
AZ’s phase 3 trial in Brazil is being coordinated by the Federal University of Sao Paulo, which said that an independent review committee had recommended that the trial should continue.
The university added in a statement that “everything is proceeding as expected, without any record of serious vaccine-related complications involving any of the participating volunteers”.
Yesterday, reports surfaced that the US arm of AZ’s COVID-19 vaccine could resume this week, after a participant in the UK-based trial developed a serious illness in September.
A standard review process triggered a voluntary pause across all global trials after the participant experienced a serious adverse event on 6 September.
According to the New York Times, the volunteer had developed transverse myelitis, a condition which is associated with viral infections and affects the spinal cord.
The UK arm of the trial has since resumed after the illness occurrence was reviewed, with regulators deeming that there was “insufficient evidence to say for certain” whether the event was related to the vaccine or not.
Trials in Japan, Brazil and South Africa have also restarted following careful reviews by international regulators, which determined that the studies are safe to resume.
Last week, Johnson & Johnson (J&J) also paused a phase 3 study of its investigational COVID-19 vaccine after a participant in the trial fell ill.
In a statement, J&J confirmed that it had paused the trial due to an “unexplained illness in a study participant”. The company offered no further details regarding the nature of the adverse event and added that the vaccine study is not currently under a clinical hold.