Oxford Vaccine Faces More Questions After AstraZeneca Admits Error

AstraZeneca faces more vaccine questions after manufacturing error. (Representational)

AstraZeneca Plc and the University of Oxford, among the front-runners in the quest to deliver a Covid-19 vaccine, face mounting questions about their trial results after acknowledging a manufacturing error.

While an announcement Monday by Astra and Oxford showed their shot was 70% effective on average in a late-stage study, the scant details released by the UK partners have sparked worries about whether regulators would clear it. In a later statement, Oxford said a difference in manufacturing processes led to some participants being given a half dose instead of a full one.

Astra and Oxford said their vaccine was 90% effective when a half-dose was given before a full-dose booster, and that two full doses showed an efficacy of 62%. But the head of the US vaccine program known as Operation Warp Speed said the next day that the dose showing the higher level of effectiveness was tested in a younger population, and that the half-dose was given to some people because of an error in the quantity of vaccine put into some vials. None of this was disclosed in Astra's original statement.