FINAL clinical trials for a coronavirus vaccine, developed by AstraZeneca and Oxford University, have been put on hold after a participant had an adverse reaction in the UK.
The vaccine is being developed by the University of Oxford in the United Kingdom in collaboration with the biopharmaceutical company AstraZeneca.
AstraZeneca described it as a “routine” pause in the case of “an unexplained illness”.
The outcome of vaccine trials is being closely watched around the world.
The AstraZeneca-Oxford University vaccine is seen as a strong contender among dozens being developed globally. Participating in a vaccine trial is a rigorous and time-consuming process. Volunteers must be carefully vetted and monitored for months, and they face some risks from potentially damaging side effects.
Hopes have been high that the vaccine might be one of the first to come on the market, following successful phase 1 and 2 testing.
Its move to Phase 3 testing in recent weeks has involved some 30 000 participants in the US as well as in the UK, Brazil and South Africa.
Phase 3 trials in vaccines often involve thousands of participants and can last several years.
All international trial sites have now been put on pause while an independent investigation reviews the safety data before regulators decide whether the trial can restart, the BBC’s Medical Editor Fergus Walsh reports.
“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 the Oxford coronavirus vaccine trial has been put on hold. Such events are routine in major trials, and happen any time a volunteer is admitted to hospital when the cause of their illness is not immediately apparent.
It is thought the trials could resume in a matter of days.
Stat News, the health website which first broke the story, said details of the UK participant’s adverse reaction were not immediately known, but quoted a source as saying they were expected to recover.
Oxford University was already using what’s known as viral vector technology to develop a vaccine for another type of coronavirus, MERS, when the current pandemic hit. Since it emerged in September 2012 in Saudi Arabia, MERS has been reported in 27 countries, with 2,494 reported cases and 858 deaths to date.
The research had reached an advanced stage when SARS-CoV-2, the novel coronavirus, was first reported in December 2019, so the scientists used their MERS technology and knowledge as the starting point for a vaccine. They inserted the SARS-CoV-2 spike protein, the studs on the COVID-19 virus that help it invade cells, into an adenovirus that causes the common cold. Weakened via genetic tweaks and unable to replicate in human cells, the adenovirus acts as the so-called viral vector.
Meanwhile, US President Donald Trump has said he wants a vaccine available in the US before 3 November’s election, but his comments have raised fears that politics may be prioritised over safety in the rush for a vaccine.
On Tuesday, a group of nine Covid-19 vaccine developers sought to reassure the public by announcing a “historic pledge” to uphold scientific and ethical standards in the search for a vaccine.
AstraZeneca is among the nine firms who signed up to the pledge to only apply for regulatory approval after vaccines have gone through three phases of clinical study.
Industry giants Johnson & Johnson, BioNTech, GlaxoSmithKline, Pfizer, Merk, Moderna, Sanofi and Novavax are the other signatories.
They pledged to “always make the safety and well-being of vaccinated individuals our top priority”.
The World Health Organization (WHO) says nearly 180 vaccine candidates are being tested around the world but none has yet completed clinical trials.
The organisation has said it does not expect a vaccine to meet its efficacy and safety guidelines to be approved this year because of the time it takes to test them safely. –