Two major coronavirus vaccine trials are set to resume in the United States after separate health scares put them on hold.
AstraZeneca’s trial had been on hold since early September, while Johnson & Johnson’s trial had been paused since earlier this month.
AstraZeneca said the US Food and Drug Administration authorised the restart on Thursday after reviewing all of the global safety data and concluding it was safe to resume.
The trial was paused after a volunteer in Britain developed a neurological condition.
The woman reportedly experienced trouble walking, weakness and pain in her arms as well as other symptoms and was hospitalised on September 5.
She was enrolled in the UK arm of the trial, which is run by the University of Oxford.
Johnson & Johnson’s trial was put on hold on October 12 due to a study participant’s “unexplained illness,” the company said.
The company said on Friday “no clear cause” was identified.
“Preparations to resume the trial in the United States are now underway,” the company said, including submissions for approval by Institutional Review Boards.
Johnson & Johnson’s statement did not specify when the trial would begin again but a source familiar with the process said it could restart at some point next week, pending IRB approval.
“There are many possible factors that could have caused the event,” the company’s statement said.
“Based on the information gathered to date and the input of independent experts, the Company has found no evidence that the vaccine candidate caused the event.”
The Johnson & Johnson vaccine trial started September 23 with a plan to recruit 60,000 patients in eight countries, including the United States.
In its statement Friday, Johnson & Johnson said discussions with regulators around the world are “progressing”.
Government health officials, as well as outside experts, have said the holds are an example of how the safety processes are working and protecting Americans from any potentially dangerous vaccines.
Regulators wanted to check to make sure any problems could not have been caused by the vaccines.
AstraZeneca has been working with Britain’s University of Oxford to develop its vaccine, one of four that have started late-stage, Phase Three trials in the United States.
The company said in the release on Thursday that results from late-stage trials are expected later this year, depending on infection rates where the trials are being conducted.