The promising results of trials of three possible coronavirus vaccines have raised hopes in the fight against the COVID-19 pandemic, which has killed more than 600,000 people and destroyed economies worldwide.
According to results published in The Lancet, early-stage clinical trials of AZD1222, a closely watched experimental vaccine that was developed by AstraZeneca and scientists at the University of Oxford in the UK, induced “robust immune responses” in participants without serious side effects. Medical journal on Monday.
The Oxford vaccine is one of 150 in development worldwide, but is considered the most advanced. US pharmacist Pfizer and China’s CanSino Biologics also reported positive responses for their candidates on Monday.
The World Health Organization (WHO) has said that any viable vaccine must be available to everyone.
Below, we take a look at the latest developments in the global vaccine race.
What is AZD1222?
The AZD1222 vaccine has been adapted from a common cold virus found in chimpanzees, with the addition of spike glycoprotein, a genetic material of the new coronavirus.
It uses the modified virus to deliver genetic instructions to cells to induce an immune response against the new coronavirus that causes COVID-19.
Between April and May, a total of 1,077 healthy adult males and females between the ages of 18 and 55 at five centers in the UK participated in the randomized and controlled Phase I and II trials of the experimental vaccine.
Each of the participants received one dose and was followed for approximately one month. Ten of them received a second dose after 28 days.
What did the results show?
In its Phase I trial, the vaccine induced so-called neutralizing antibodies, the type that prevents the virus from infecting cells, in 91 percent of people one month after receiving a dose, and in the 10 subjects who received a second dose,after 28 days, echoing a similar test in pigs.
These levels were on par with the antibodies produced by people who had survived a COVID-19 infection, a key benchmark for potential success.
Oxford principal investigator Sarah Gilbert said the trial was unable to determine whether one or two doses would be needed to provide immunity.
The vaccine also induced the body to produce T cells, activating a second part of the immune system that experts increasingly believe will be important for a lasting immune response.
What’s the reaction?
While welcoming the first results, the scientific community also urged caution, with some predicting it would take until the middle of next year to find out if the vaccine really works.
Andrew Pollard, principal investigator of the Oxford study, said they were “a major milestone” in efforts against the coronavirus, but added that the researchers “are now rapidly moving forward to try to assess whether the vaccine really protects the population by carrying out great actions. ” scale trials. “
Mene Pangalos, head of research at AstraZeneca, said in a statement that Monday’s data “increases our confidence that the vaccine will work and allows us to continue our plans to manufacture the vaccine at scale for broad and equitable access worldwide.”
Mike Ryan, WHO chief emergency officer, praised the “good news” of the results, but warned: “There is a long way to go.”
UK Prime Minister Boris Johnson, whose government has helped finance the project, called the announcement “very positive news.”
Whats Next?
Before a vaccine can be approved for mass production and global distribution, it has to go through three stages, sometimes four, of human clinical trials. Provoking an immune reaction is the first part of vaccine development.
Phase III trials, already underway in the UK, South Africa and Brazil, are looking at the optimal dose and how much protection vaccinated people have when they are actually exposed to the coronavirus. Late-stage trials should also begin in the United States, where the prevalence is highest.
“There is still a long way to go,” said Gilbert, the Oxford researcher.
“We still need to see how the vaccine works in older people, who are more at risk for serious disease than the people we have vaccinated in this study,” he said. “So that’s the topic of future work, and there will be more posts to come.”
Wafaa el-Sadr, a professor of epidemiology and medicine at Columbia University, told Al Jazeera that a six-month deadline would likely determine whether the vaccine is safe and effective for mass production.
AstraZeneca has signed agreements with governments around the world to supply the vaccine, should it obtain regulatory approval. It has signed agreements to produce and supply more than two billion doses of the vaccine, with 300 million doses destined for the United States.
What other vaccines are being developed?
More than 150 other COVID-19 vaccines are being developed worldwide.
New data released Monday showed that a candidate developed by CanSino Biologics Inc and the China Military Research Unit appeared to be safe and induced an immune response in the majority of the 508 healthy volunteers aged 18-83 years who received a dose of the vaccine.
About 77 percent of the study volunteers experienced fever, fatigue, headache, or injection site pain, side effects that are not considered serious.
The results of another, smaller study in Germany of a different type of vaccine using ribonucleic acid (RNA), a chemical messenger that contains instructions for making proteins, were also published by German biotech company BioNTech and Pfizer.
In the study of 60 healthy adults, which was not peer-reviewed, the vaccine induced virus-neutralizing antibodies in those who received two doses, a result that was in line with a previous early-stage trial in the United States.
While the pace of the global vaccine race is unprecedented, experts caution that producing enough doses of a successful candidate can be as difficult as developing it in the first place.
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