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One of the most high-profile vaccine trials has resumed, but only in the UK so far, after getting the all-clear from health regulators.
AstraZeneca and the University of Oxford have confirmed that their phase-three trial of the AZD1222 Covid-19 vaccine candidate can resume after receiving approval from the UK Medicines Health Regulatory Authority (MHRA). Last week, the trial was put on hold after one of its participants experienced a serious adverse reaction.
While this go-ahead is limited to the UK, AstraZeneca issued a statement saying: “The standard review process triggered a voluntary pause to vaccination across all global trials to allow review of safety data by independent committees and international regulators.
“The UK committee has concluded its investigations and recommended to the MHRA that trials in the UK are safe to resume … The company will continue to work with health authorities across the world and be guided as to when other clinical trials can resume to provide the vaccine broadly, equitably and at no profit during this pandemic.”
Prior to the pause, AstraZeneca had begun phase-three trials in the US, with plans to recruit up to 30,000 people to help test the safety and efficacy of the vaccine candidate. It is also conducting trials in Brazil and South Africa.
Reason behind the pause
The AZD1222 vaccine uses an adenovirus that contains a gene of a SARS-CoV-2 protein and is designed to induce the immune system to respond to the virus.
While the side effect experienced by the patient in the trial was not confirmed, Stat News reported that a woman in the UK had shown neurological symptoms consistent with a serious and rare spinal inflammatory disorder called transverse myelitis. AstraZeneca’s chief executive, Pascal Soriot, was reported to have said on a private call with investors that the woman received the vaccine candidate rather than a placebo.
He is also reported to have said that the trial was previously paused in July when another patient experienced neurological symptoms after receiving the drug, however it was later found that the participant was diagnosed with multiple sclerosis and it was ruled as unrelated to the vaccine.
Findings on phase-one and phase-two trials published to The Lancet in July showed that approximately 60pc of 1,000 study participants given the AZD1222 vaccine experienced some side effects. This included headaches, fever, muscle pain and injection reactions, which are deemed either mild or moderate and were reported to have subsided during the study.
