LONDON (Reuters) – An experimental vaccine developed by AstraZeneca and the University of Oxford against the new coronavirus produced an immune response in early-stage clinical trials, data showed on Monday, preserving hope that it could be in use by the end of the year.
Called AZD1222, the vaccine has been described by the chief scientist at the World Health Organization as the leading candidate in a global race to stop a pandemic that has killed more than 600,000 people.
More than 150 potential vaccines are in various stages of development, and U.S. pharmacist Pfizer and CanSino Biologics of China also reported positive responses to their candidates on Monday.
The AstraZeneca and Oxford University of Great Britain vaccine did not cause serious side effects and elicited immune responses of antibodies and T cells, according to the results of the trial published in the medical journal The Lancet, with the strongest response observed in people who received two doses.
British Prime Minister Boris Johnson, whose government has helped finance the project, hailed the results as “very positive news,” although investigators cautioned that the project was still at an early stage.
“There is still a lot of work to be done before we can confirm whether our vaccine will help control the COVID-19 pandemic,” said vaccine developer Sarah Gilbert. “We still don’t know how strong the immune response is that we must elicit to effectively protect against SARS-CoV-2 infection.”
AstraZeneca shares rose 10%, but then abandoned most of those gains, to close 1.45% on the day.
AstraZeneca has signed agreements with governments around the world to supply the vaccine if it is effective and gets regulatory approval. He has said he will not seek to take advantage of the vaccine during the pandemic.
AZD1222 was developed by Oxford and licensed by AstraZeneca, which has put it into large-scale trials at advanced stages to test its effectiveness. It has signed agreements to produce and supply more than 2 billion doses of the vaccine, with 300 million doses destined for the United States.
Pascal Soriot, executive director of AstraZeneca, said the company was on track to produce doses for September, but that it expects it to be available this year depends on how quickly late-stage trials can be completed, given the decline in prevalence. of the virus. in Great Britain.
Late-stage trials are underway in Brazil and South Africa and are expected to start in the United States, where the prevalence is highest.
TARGET TWO DOSE
The results of the trial showed a stronger immune response in 10 people who received an additional dose of the vaccine after 28 days, which was echoed by a trial in pigs.
Gilbert of Oxford said the early-stage trial was unable to determine whether one or two doses would be needed to provide immunity.
“We may not need two doses, but we want to know what we can achieve,” he told reporters.
AstraZeneca chief biopharmacy officer Mene Pangalos said the company was leaning toward a two-dose strategy for later-stage trials and did not want to risk a single or lower dose that might not work.
The levels of antibodies generated were “in the region” of those seen in convalescent patients, he said.
The trial included 1,077 healthy adults aged 18-55 with no history of COVID-19. The researchers said the vaccine caused minor side effects more often than a control group, but some of these could be reduced by taking the pain reliever paracetamol, which is also known as acetaminophen.
Alistair Smout Report; additional reports from Pushkala Aripaka and Kate Kelland; Edmund Blair, Mark Potter, Carmel Crimmins and Timothy Heritage edition
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