AstraZeneca COVID-19 Vaccine Trial Halted

Drug maker AstraZeneca, which has been developing of one of the leading vaccine candidates against COVID-19 (along with Oxford University), has released a statement saying it has paused a late-stage trial of the vaccine to review safety data. Large-scale, phase III trials of the vaccine had begun in the U.S., Britain, Brazil and South Africa. The pause will call a halt to the AstraZeneca studies being conducted in the U.S. and other countries.

The same day as the announcement about the halt to the trial, AstraZeneca and eight other drug makers pledged publicly to uphold high ethical and scientific standards as they developed their vaccines.

A patient participating in the U.K. study who got the vaccine developed a “potentially unexplained” illness. AstraZeneca declined to provide further information about the possible side effect, according to STAT. Any serious or unexpected reactions that arise during vaccination trials in humans must be investigated.

According to AstraZeneca, the illness could be coincidental rather than related to the vaccination. The company says it is working quickly to review the event so that the trial can continue. Temporary holds during large medical studies are not unusual. However, University of Washington researcher Deborah Fuller (who is working on an unrelated COVID-19 vaccine) says that the unexplained illness most likely was something serious enough to require hospitalization. She adds that halting the study to review the issue is the right thing to do, although in and of itself, the incident is not alarming.

Part of the reason for final large-scale trials of drugs and viruses is to ferret out rarer side effects from the treatment and to ensure that it is safe. Phase III trials also given a better gauge of the effectiveness of a treatment.

Vaccines from Moderna, Inc., and from Pfizer/BioNTech are also in phase III trials, but those vaccines do not use the same mechanism against the virus as the AstraZeneca vaccine.


Disclaimer: This article does not provide medical advice. Do not take action based solely on this article and always consult with an appropriate healthcare professional. This article is purely for informational purposes.

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