AstraZeneca Places Holds On Trials For Potential COVID-19 Vaccine

ADZ1222 trails temporarily on hold The UK-based pharmaceutical company, AstraZeneca, has worked closely with Oxford University to create a coronavirus (COVID-19) vaccine. The vaccine is currently in Phase 3...

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ADZ1222 trails temporarily on hold

The UK-based pharmaceutical company, AstraZeneca, has worked closely with Oxford University to create a coronavirus (COVID-19) vaccine. The vaccine is currently in Phase 3 study testing on participants in the U.S. and U.K. but announced they have put the trial on hold due to a severe adverse reaction in a U.K. participant.

AstraZeneca disclosed that they initiated a hold on the Stage 3 trials for the ADZ1222 vaccine in accordance with the company’s “standard review process triggered a pause to vaccination to allow the review of safety data.” The participant experiencing the adverse reaction is expected to recover but they’re still studying the nature and cause of the adverse reaction.

A spokesperson for AstraZeneca explained the hold in the trial as a routine action that is required in cases of unexplained illness in the trial. Placing a hold on the ADZ1222 trials maintains the integrity of the trials during the further investigation while expediting the review to minimize the impact on the trial timeline.


This is the first Phase 3 COVID-19 vaccine trial to be put on hold and researchers in other trials are looking into similar cases with adverse reactions. The ADZ1222 Phase 3 trials are taking place in 62 sites across the U.S. along with Phase 2/3 trials started in the U.K., South Africa, and Brazil.

The ADZ1222 vaccine utilizes an adenovirus that carries a gene for one of the SARS-CoV-2 proteins which are the virus that causes COVID-19. The vaccine is designed to induce the immune system to generate a protective response against SARS-2.

The U.S. Phase 3 trials are aiming to enroll approximately 30,000 participants through 80 sites across the country according to the National Institutes of Health. AstraZeneca reassures they’re committed to creating a safe trail for participants with the highest standards of conduct and taking precautionary measures.