Late-stage studies of a highly-anticipated COVID-19 vaccine candidate, being developed by AstraZeneca and the University of Oxford, have been put on temporary hold due to a suspected serious adverse reaction in a participant in the United Kingdom.
The company is now investigating if a report of a patient with a serious side effect is linked to the shot.
AstraZeneca, a frontrunner in the race for a COVID-19 vaccine, said in a statement on September 8 that the company’s “standard review process triggered a pause to vaccination to allow review of safety data.”
The AstraZeneca-Oxford vaccine is seen as one of the most promising of the vaccines against the novel coronavirus infection that are currently under development.
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AstraZeneca didn’t reveal any information about the possible side effect except to call it a potentially unexplained illness.
Frequently Asked Questions
A vaccine works by mimicking a natural infection. A vaccine not only induces immune response to protect people from any future COVID-19 infection, but also helps quickly build herd immunity to put an end to the pandemic. Herd immunity occurs when a sufficient percentage of a population becomes immune to a disease, making the spread of disease from person to person unlikely. The good news is that SARS-CoV-2 virus has been fairly stable, which increases the viability of a vaccine.
There are broadly four types of vaccine — one, a vaccine based on the whole virus (this could be either inactivated, or an attenuated [weakened] virus vaccine); two, a non-replicating viral vector vaccine that uses a benign virus as vector that carries the antigen of SARS-CoV; three, nucleic-acid vaccines that have genetic material like DNA and RNA of antigens like spike protein given to a person, helping human cells decode genetic material and produce the vaccine; and four, protein subunit vaccine wherein the recombinant proteins of SARS-COV-2 along with an adjuvant (booster) is given as a vaccine.
Vaccine development is a long, complex process. Unlike drugs that are given to people with a diseased, vaccines are given to healthy people and also vulnerable sections such as children, pregnant women and the elderly. So rigorous tests are compulsory. History says that the fastest time it took to develop a vaccine is five years, but it usually takes double or sometimes triple that time.
STAT, a website reporting on health and medical topics, first reported the pause in testing, saying the possible side effect occurred in the United Kingdom.
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An AstraZeneca spokesperson confirmed the pause in vaccinations covers studies in the US and other countries. Late last month, AstraZeneca began recruiting 30,000 people in the US for its largest study of the vaccine.
It is also testing the vaccine, developed by Oxford University, in thousands of people in Britain, and in smaller studies in Brazil and South Africa.
Two other vaccines are in huge, final-stage tests in the United States, one made by Moderna Inc. and the other by Pfizer and Germany’s BioNTech. Those two vaccines work differently than AstraZeneca’s, and the studies already have recruited about two-thirds of the needed volunteers.
Temporary holds of large medical studies aren’t unusual, and investigating any serious or unexpected reaction is a mandatory part of safety testing. AstraZeneca pointed out that it’s possible the problem could be a coincidence; illnesses of all sorts could arise in studies of thousands of people.
We are working to expedite the review of the single event to minimize any potential impact on the trial timeline, the company statement said.
The development came the same day that AstraZeneca and eight other drugmakers issued an unusual pledge, vowing to uphold the highest ethical and scientific standards in developing their vaccines.
The announcement follows worries that President Donald Trump will pressure the US Food and Drug Administration to approve a vaccine before its proven to be safe and effective.
The U.S. has invested billions of dollars in efforts to quickly develop multiple vaccines against COVID-19. But public fears that a vaccine is unsafe or ineffective could be disastrous, derailing the effort to vaccinate millions of Americans.
Representatives for the FDA did not immediately respond to requests for comment Tuesday evening.
(With inputs from Associated Press)
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