Accidental AstraZeneca Vaccine Dosage Raises Concern

A half-dose of AstraZeneca’s Covid-19 vaccine, followed by a full dose later, appeared to be more effective than administering two full doses.

KUALA LUMPUR, Nov 26 — The AstraZeneca-Oxford Covid-19 vaccine has begun to lose confidence among scientists and industry experts, after developers admitted mistakes in administering the vaccine.

The New York Times noted that fewer than 2,800 volunteers received only half-strength of the initial dose, compared to almost 8,900 people who received the full two doses. AstraZeneca accepted the mistake that occurred in the vaccine dosage received by their volunteers.

AstraZeneca’s accidental usage of a half-dose vaccine appeared to be more effective compared to a full dose.

The vaccine showed 90 per cent effectiveness when participants received half dose of the vaccine first, followed by a full dose one month later. But it was only 62 per cent effective when volunteers received two full doses. The average efficacy, said the vaccine developers, 70 per cent.

AstraZeneca was unable to explain the reason for these differences in effectiveness when different doses of vaccine were used on the volunteers.

“I think that they have really damaged confidence in their whole development programme,” Geoffrey Porges, an analyst for the investment bank SVB Leerink was quoted as saying.

Nevertheless, AstraZeneca claimed that the trials “were conducted to the highest standards”.

According to Michele Meixell, a spokeswoman for AstraZeneca, the trials were discontinued after discovering the dosage mistake by a contractor.

Although the UK pharmaceutical company involved 131 symptomatic Covid-19 patients in its initial analysis, a breakdown of the patients’ category — such as how many coronavirus infections were found respectively in those who received the half-strength first dose, the full initial dose, and the placebo — was not announced.

“The press release raised more questions than it answered,” John Moore, a professor of microbiology and immunology at Weill Cornell Medical College, was quoted as saying.

Besides that, AstraZeneca also combined the results of two differently designed clinical trials that were conducted in Brazil and Britain, which the New York Times noted did not follow standard practice in reporting drug and vaccine trial results.

Nicolas Pangalos, the executive vice president at AstraZeneca, reportedly stated that the miscalculation in the administration of vaccines did not harm any participants and that the half dose was purely accidental.

“The reality is, it could end up being quite a useful mistake,” Pangalos was quoted saying.

“It wasn’t putting anyone in danger. It was a dosing error. Everyone was moving very fast. We corrected the mistake and continued on with the study, with no changes to the study, and agreed with the regulator to include those patients in the analysis of the study as well.”

Pangalos also reportedly stated that participants aged 55 and below received the half-dose of vaccine weeks before the error was discovered.

It is to be noted that unlike Moderna and Pfizer-BioNTech’s Covid-19 candidate vaccines that require ultra-cold storage, the Oxford-AstraZeneca vaccine can be stored, transported, and handled at normal refrigerated conditions between two and eight degrees’ Celsius for at least six months and can be administered within existing health care settings.

Earlier, The Guardian reported that the AstraZeneca vaccine will be sold at cost price to low and middle-income countries.

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