Unexplained illness halts global trials of AstraZeneca coronavirus vaccine

AstraZeneca halts global trials of coronavirus vaccine due to unexplained illness by one participant
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Pharma giant AstraZeneca has announced that it decided to pause worldwide trials of its coronavirus vaccine due to an unexplained illness suffered by a volunteer.

The decision of AstraZeneca to halt the trials of its coronavirus vaccine following an unexplained illness in one of the participants is a standard precaution in vaccine trials made to ensure that experimental vaccines do not cause serious reactions among participants.

In a statement, the drug maker said: “As part of the ongoing randomized, controlled global trials of the Oxford coronavirus vaccine, our standard review process triggered a pause to vaccination to allow review of safety data.”

Pausing the trials

AstraZeneca’s vaccine, dubbed the Oxford vaccine because it was developed in partnership with the University of Oxford, is being tested in various parts of the world, including the US, the UK, Latin America, Asia, Europe and Africa.

The pharma firm said: “This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials.”


“In large trials, illnesses will happen by chance but must be independently reviewed to check this carefully. We are working to expedite the review of the single event to minimize any potential impact on the trial timeline. We are committed to the safety of our participants and the highest standards of conduct in our trials,” AstraZeneca explained.

While it’s usually a Data and Safety Monitoring Board (DSMB) that monitors trials for adverse events and can order a pause or halt a trial, the firm did not specify who ordered the stoppage.

In vaccine trials, the most common side effects include fever, headache, soreness at the injection site and muscle pain.

Starting Phase 3

Last week, the British pharmaceutical firm became the third company to begin Phase 3 trials in the US. Along with the other two drugmakers currently doing Phase 3 trials, Moderna and Pfizer/BioNTec, AstraZeneca received funding from the federal government.

AstraZeneca stated that it is “recruiting up to 30,000 adults aged 18 years or over from diverse racial, ethnic and geographic groups who are healthy or have stable underlying medical conditions, including those living with HIV, and who are at increased risk of infection from the SARS-CoV-2 virus.”

In the trials, participants will be given two active or placebo doses, spaced four weeks apart. The firm is currently conducting Phase 3 trials in the UK, Brazil and South Africa and is eyeing to start similar trials in Japan and Russia.

AstraZeneca signs pledge

Earlier on Tuesday, the drug company joined eight other firms in signing a pledge to not seek premature government approval for any coronavirus vaccine. They pledged that they would wait until there is sufficient data showing any potential vaccine worked safely.

The pledge read: “We, the undersigned biopharmaceutical companies, want to make clear our on-going commitment to developing and testing potential vaccines for COVID-19 in accordance with high ethical standards and sound scientific principles.”

It was signed by the chief executive officers (CEOs) of AstraZeneca, BioNTech GlaxoSmithKline, Johnson & Johnson, Merck, Moderna, Novavax, Pfizer and Sanofi.