AstraZeneca Covid-19 vaccine study put on hold due to suspected adverse reaction
AstraZeneca put their Phase 3 study on hold. A volunteer suffered a serious adverse reaction during the study with this Covid-19 vaccine candidate. The company will review the safety data to better understand what happened. Currently there are 9 vaccine candidates in Phase 3.
AstraZeneca started this Phase 3 study weeks ago in the US. 62 sites across the US were scheduled for this study, although some have not yet started enrolling participants and will probably pause enrollment. The company conducted Phase 2/3 trials in the U.K., Brazil, and South Africa.
A variety of reactions can be considered serious adverse reactions. For example, symptoms leading to hospitalization, life-threatening disease, and even mortality. It is possible that a volunteer in the UK cohort suffered the adverse event.
The AstraZeneca vaccine, AZD1222, applies an adenovirus with a gene for a protein in SARS-Cov-2, the virus causing Covid-19. The goal is for the adenovirus to produce an immune response against the virus. There is no approved vaccine using this method. This approach was applied as an experimental vaccine for other viruses, including Ebola.
It is not yet known how clinical sites across the U.S. will handle the hold. Clinical holds in ongoing trials usually include a freeze to new volunteers’ participation and dosing of current volunteers.
An AstraZeneca spokesperson expressed the following “in large trials illnesses will happen by chance but must be independently reviewed to check this carefully.” The spokesperson mentioned that they are “committed to the safety of our participants and the highest standards of conduct in our trials.”