COVID-19: Oxford suspends trial of promising vaccine after adverse reaction on subject

A coronavirus vaccine developed by the University of Oxford has been halted temporarily following the discovery of certain side effects on test subjects.

According to Bloomberg, the pause, first reported by Stat on Tuesday, occurred due to a suspected serious adverse reaction in a single person participating in the trial in the UK.

While the health problems the individual experienced has not been disclosed, the situation will add steam to the concerns of health experts calling for caution in the race for a vaccine for the highly contagious COVID-19.

The pause came amid growing anxiety about the possibility that President Donald Trump could try to rush a coronavirus vaccine ahead of the U.S. election.

The Oxford developed vaccine is just one among more than 150 coronavirus vaccines in development across the world. Hopes are high that by the end of the year, there could be at least half a dozen different coronavirus vaccines in clinical trials to bring one to market in record time to ease the global crisis.


Coronavirus still poses a significant threat, but there are no vaccines proven to protect the body against the disease it causes – COVID-19.

Called ChAdOx1 nCoV-19, the Oxford trial vaccine, also led by the pharmaceutical company, AstraZeneca, is being developed at unprecedented speed.

The BBC reported how the UK ordered about 100 million doses of the vaccine which is made from a genetically engineered virus that causes the common cold in chimpanzees.


Asides the latest development, no serious adverse events were reported during the early trials of the vaccines.


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The Phase 1 and 2 trials of the vaccine, tested in 1,077 patients showed promising “neutralizing” antibodies in around 90 per cent of participants, Bloomberg reported.

Around 60 per cent of patients reported mild or moderate side effects, including fever, headaches, and muscle aches, all of which were resolved in the course of the trials.

Scientists said the vaccine has been heavily modified, first so it cannot cause infections in people and also make it “look” more like coronavirus. But the “unexplained illness” it caused on a single test subject have put doubts on the much-touted cure.

A spokesperson for AstraZeneca said that the trial was paused as a precautionary measure so that scientists could investigate whether the illness is in fact linked to the vaccine, Bloomberg reported.

“This is a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials,” the spokesperson said.

Coronavirus vaccine race

The World Health Organisation is coordinating global efforts to develop a vaccine, with an eye toward delivering two billion doses by the end of 2021.

Like all vaccines, the one against COVID-19 is essentially expected to instruct the immune system to mount a defense, which is sometimes stronger than what would be provided through natural infection and comeswith fewer health consequences.

Last month, Russia registered the first COVID-19 vaccine becoming the first nation in the world to lay claim to such a feat, although under controversial circumstances.

The first peer-reviewed results of Phase 1 and Phase 2 clinical trials of Russia’s coronavirus vaccine, which is named Sputnik-V, were published in the medical journal, The Lancet, last Friday, according to CNN.

However, Russia faced criticism last month when it announced the coronavirus vaccine for public use, even before Phase 3 trials are completed.

A vaccine must complete three phases of trials – including randomized controlled trials on large patient groups – before it could be considered for approval, according to WHO.

Nigeria is among the first African countries to receive samples of the COVID-19 vaccine from Russia.

Health experts in South Africa, the first African country to receive the samples, are calling for caution in placing much hope on the new vaccine. They said little is known about the efficacy of the vaccine.



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