Manufacturing error causes AstraZeneca to face more COVID-19 vaccine related questions

London: AstraZeneca and the University of Oxford face mounting questions about their COVID-19 vaccine trial results after acknowledging a manufacturing defect last week.

Astra and Oxford revealed that their shots were 70% efficient on average in a late-stage study and this detail released by the UK partners has sparked worries.

Their vaccine was 90% effective when a half-dose was given before a full-dose booster. Two full doses showed an efficiency of 62%. However, the head of the US vaccine program known as Operation Warp Speed said that the dose showed a higher level of effectiveness because it was tested on the younger population.

Oxford admitted that a difference in the manufacturing process had led to the later phase of the trial showing a half-dose instead of a full one.

"The methods for measuring the concentration are now established and we can ensure that all batches of vaccine are now equivalent," said the university.

Sam Fazeli, a Bloomberg Intelligence Analyst said that the explanation to the divergent efficacy is either patient demographics or chance. "Either way, approval based on the current data means people will be inoculated with a vaccine the true efficiency of which is unknown," he added.

Michele Meixell, a spokesman for Astra said that the trials were conducted "to the highest standards" and confirms that more analysis will be done to refine its efficacy reading.

In an interview on Wednesday, Menelas Pangalos, the AstraZeneca executive-in-charge defended the company's handling of the testing and its public disclosures.

He said the error in the dosage was made by a contractor, and that, once it was discovered, regulators were immediately notified and signed off on the plan to continue testing the vaccine in different doses.

AstraZeneca was the third company this month with encouraging results. Depending on the strength at which the doses were given, the vaccine appeared to be either 90% or 62% effective. The average efficacy, the developers said, was 70%.

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