Oxford's COVID-19 Vaccine Phase-3 Trials Paused Due To Serious Adverse Effect

The phase 3 clinical trial of a COVID-19 vaccine candidate developed by Oxford University and AstraZeneca biopharmaceutical firm has been halted because of a “suspected serious adverse reaction” in a participant of the study, STAT reported.

The vaccine candidate, dubbed AZD1222, is among the few promising COVID-19 vaccines, which recently entered clinical testing in the UK and the US. According to the spokesperson, putting the trial on hold is just a routine action they have to take when a potentially unexplained illness comes up in one of the trials. The spokesperson said the pause was triggered due to a review process.

Normally, clinical trials are paused in order to investigate the nature of adverse events. This is how clinical trials work and also why researchers have to carry out strict phase-3 trials. These trials are designed to make sure the vaccine is safe before it’s released for public use. Infectious diseases epidemiologist Hassan Vally said:

“This, while disappointing, should reassure us that the proper processes and safety precautions are being followed, despite the urgency of this pandemic. The reality is that these reactions do occur and they need to be examined closely.”

For now, it’s unclear what the nature of the adverse reaction is, but an investigation is taking place and the affected participant is believed to be from the UK. It not clear if the reaction is linked to this vaccine or not. According to immunology professor Madgalena Plebanski from RMIT University, when one out of 50,000 participants has an unexplained adverse reaction in a human trial, it’s most likely that it has nothing to do with the vaccine, “No need to panic yet.”

While Vally says there needs to be more information around the event, other researchers say it might be more than just minor side effects.

The event is affecting other vaccine trials by AstraZeneca while researchers of other trials are reviewing their own data to look for similar adverse reactions.

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