Oxford University Vaccine Trial Paused after Participant Falls Ill

The final clinical trials for coronavirus vaccine developed by AstraZeneca and Oxford University have been halted after a participant had an adverse reaction in the United Kingdom, BBC reports.

AstraZeneca described it as a "routine" pause in the case of "unexplained illness."

The outcome of the vaccine trials is being monitored closely around the world.

AstraZeneca-Oxford University vaccine is seen as a strong contender among dozens of globally developed vaccines.

Hopes have been high that the vaccine might be one of the first to be launched on the market following successful phase 1 and phase 2 testing.

Approximately 30,000 participants in the U.S. as well as in the United Kingdom, Brazil and South Africa have participated in phase 3 testing in recent weeks. Phase 3 vaccine trials often involve thousands of participants and may last several years.

What have the developers said?

All international trial sites have now been halted while an independent investigation reviews safety data before regulators decide whether the trial can be restarted, reports BBC Medical Editor Fergus Walsh.

"In large trials, illnesses will happen by chance but must be independently reviewed to check this carefully", an Oxford University spokesperson said.

This is the second time that the Oxford coronavirus vaccine trial has been put on hold, our correspondent notes. Such events are routine in major trials, and occur whenever a volunteer is admitted to the hospital when the cause of his illness is not immediately apparent.

It is thought that the trials could resume in a matter of days.

Stat News, the health website that first broke the story, said the details of the adverse reaction of the UK participant were not immediately known, but quoted the source as saying they were expected to recover. 

US President Donald Trump said he wanted a vaccine to be available in the US before the November 3 elections, but his comments raised fears that politics could be prioritized over safety in the run-up to a vaccine.

On Tuesday, a group of nine Covid-19 vaccine developers sought to reassure the public by announcing a "historic commitment" to upholding scientific and ethical standards in the search for a vaccine.

AstraZeneca is among the nine companies that have signed up to the promise to apply for regulatory approval only after three phases of the clinical study have been completed.

The other signatories are Johnson & Johnson, BioNTech, GlaxoSmithKline, Pfizer, Merk, Moderna, Sanofi and Novavax.

They promised to "always make the safety and well-being of vaccinated individuals our top priority."

The World Health Organization ( WHO ) reports that nearly 180 vaccine candidates are being tested around the world, but no clinical trials have yet been completed.

The organisation has stated that it does not expect the vaccine to meet its efficacy and safety guidelines in order to be approved this year because of the time it takes to test them safely.

Thomas Cueni, Director-General of the International Federation of Pharmaceutical Manufacturers, shared similar sentiments. The body of the industry represents the companies that have signed the pledge.

Despite this, China and Russia have begun to inoculate some key workers with domestically developed vaccines. All of these are still listed by the WHO as being in clinical trials.

Meanwhile, the US National Regulator, the Food and Drug Administration (FDA), has suggested that coronavirus vaccines may be approved prior to the completion of a third phase of clinical trials.

It also emerged last week that the US Centers for Disease Control and Prevention had urged states to consider waiving certain requirements in order to be ready to distribute a potential vaccine by 1 November-two days before the presidential election on 3 November.

Although President Trump suggested that a vaccine might be available before the election, his Democratic rival Joe Biden expressed his skepticism that Mr Trump would listen to the scientists and implement a transparent process.