AstraZeneca’s Covid-19 vaccine shows average efficacy of 70%
The coronavirus vaccine developed by the University of Oxford and drug maker AstraZeneca has shown an average efficacy of 70 percent, depending on dosage, the partners said as they announced clinical trial results.
The developers revealed the preliminary results on Monday, following trials conducted in the UK and Brazil. Depending on the dosage, the vaccine showed varying efficacy of up to 90 percent, while the Pfizer vaccine is 95-percent effective and Russia’s Sputnik V is 92-percent effective.
“One dosing regimen showed vaccine efficacy of 90 percent when AZD1222 was given as a half dose, followed by a full dose at least one month apart, and another dosing regimen showed 62 percent efficacy when given as two full doses at least one month apart,” the AstraZeneca developers said in a statement, adding, “analysis from both dosing regimens resulted in an average efficacy of 70 percent.”Also on rt.com UK terrorism chief calls for ‘national debate’ on criminalizing doubts about Covid-19 vaccine
AstraZeneca’s CEO Pascal Soriot said the vaccine’s “efficacy and safety” showed it will be highly effective against the coronavirus and it will have an “immediate impact” on the Covid-19 crisis.
The announcement was welcomed by UK Health Secretary Matt Hancock who said the preliminary trial results were “fantastic news.”
“These figures ... shows that the vaccine in the right dosage can be up to 90 percent effective,” he told Sky News. “We’ve got 100 million doses on order and should all that go well, the bulk of the rollout will be in the new year.”
The pilot vaccination program is expected to begin next month, Hancock added, expressing hope that “sometime after Easter things will be able to start to get back to normal.”
The rather surprising results of the clinical tests – with higher vaccine dosages turning out to be significantly less efficient – might stem from the fact that a patient develops immunity to the chimpanzee adenoviral vector used in the AstraZeneca vaccine, developers of Russia’s Sputnik V suggested later on Monday. The Russian anti-coronavirus jab circumvented such issues by using two different human adenoviral vectors in its two shots.
The possible reason for 62% efficacy of AstraZeneca’s full dose regiment is that immunity to chimpanzee adenoviral vector from the 1st shot makes 2nd shot not effective. #SputnikV addresses this issue by using two different human adenoviral vectors for two shots (92% efficacy)— Sputnik V (@sputnikvaccine) November 23, 2020
AstraZeneca has become the fourth company to publicly announce efficacy of its coronavirus vaccine. Russia became the first country to register a vaccine against coronavirus, with its solution, dubbed Sputnik V, showing around 92 percent effectiveness during trials. Earlier this month, Pfizer and America’s Moderna published results of testing their vaccines, which showed some 95 percent efficacy.
All the vaccines available have been made using different tech – while Russia's Sputnik V is based on a human adenoviral vector, Pfizer’s and Moderna’s drugs utilized new messenger RNA technology. AstraZeneca’s vaccine is based on chimpanzee adenovirus, which proved to be the less trusted approach, a recent YouGov poll has shown. While the approach taken by developers of Sputnik V, on the contrary, garnered some nine times higher levels of trust.
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