A day after acknowledging that their COVID-19 vaccine was 90 percent effective when a half-dose was given before a full-dose booster, AstraZeneca Plc and the University of Oxford are facing questions on their trial results.
Earlier on Monday, AstraZeneca and Oxford had claimed that their shot was 70 percent effective on average in a late-stage study. Later, they said that difference in manufacturing processes led to some participants being given a half dose instead of a full one, reports Bloomberg.
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Head of the US Operation Warp Speed program has raised an alarm stating that the half-dose was given to some people as a result of an error in the quantity of vaccine put into some vials.
Following this, scientists and investors were rattled on the way vaccine developers have handled the large trial, accusing the firms of sketchy details. AstraZeneca and Oxford, meanwhile, had stated that two full doses showed an efficacy of 62 percent.
"Any time you have confusion in trials it’s not a good thing because it effectively removes any kind of credibility you had. I think there will be a lot more scrutiny of Astra’s product due to the manufacturing issue," Bloomberg quoted EdenTree Investment Management's fund manager Ketan Patel as saying.
However, the University of Oxford claimed that they discussed with regulators when it was apparent that a lower dose was used. The varsity also stated that an agreement was reached to push ahead with the two regimens.
"The methods for measuring the concentration are now established and we can ensure that all batches of vaccine are now equivalent," Oxford said. Also, AstraZeneca's spokesperson claimed that they are analysing the results to refine the efficacy reading.
With the US drugmakers, Pfizer-BioNTech SE and Moderna claiming about 95 percent effectiveness in preliminary analyses of trials, US Operation Warp Speed program's Dr Moncef Slaoui had said the first Americans to receive a coronavirus vaccine could get it as soon as December 11.
Also, Pfizer had submitted an application to the US Food and Drug Administration for emergency use authorisation last Friday. However, the findings of AstraZeneca's vaccine fired up optimism that an end to the pandemic is in sight.