AstraZeneca's COVID-19 vaccine trial in the United States is expected to resume as early as this week after the US Food and Drug Administration completed its review of a serious illness.
The large, late-stage trial has been on hold since September 6, after a participant in the company's UK trial fell ill with what was suspected to be a rare spinal inflammatory disorder called transverse myelitis.
Sources briefed say they have been told the trial could resume later this week. It is unclear how the FDA will characterise the illness, they say.
The FDA has declined to comment.
It is understood the agency is requiring researchers conducting the trial to add information about the incident to consent forms signed by study participants.
UK regulatory officials previously reviewed the illness and determined there was "insufficient evidence to say for certain" it was or was not related to the vaccine.
That permitted the trial to resume in the UK, according to a draft of the updated consent form.
"In this case, after considering the information, the independent reviewers and MHRA (Medicines and Healthcare products Regulatory Agency) recommended that vaccinations should continue," it stated.
"Close monitoring of the affected individual and other participants will be continued."
Regulators in Brazil, India and South Africa have also allowed AstraZeneca to resume its vaccine trials there.
AstraZeneca, which is developing the vaccine with Oxford University researchers, had been seen as a frontrunner in the race to produce a vaccine for COVID-19 until its trials were put on hold.
Early data from large-scale trials in the United States of vaccines from Pfizer Inc and Moderna Inc are expected some time next month.
Johnson & Johnson last week paused its Phase III COVID-19 vaccine trial to investigate an unexplained illness in one of the study participants.
At the time of the announcement, the company did not know whether the volunteer had been given its vaccine or a placebo.
A J&J spokesman on Tuesday said the study remains on pause as the company continues its review of medical information before deciding to restart the trial.
Vaccines are seen as essential to helping end the pandemic that has battered economies around the world and claimed more than a million lives - over 220,000 of them in the United States.
Australian Associated Press
