Covid-19: a dosing error for the AstraZeneca vaccine?

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In this study, not all trial participants received the same dose of vaccine. Some only received half a dose. Disclosures that question the actual effectiveness of the vaccine.

On November 22, the British laboratory AstraZeneca announced that its two-injection vaccine, developed with the University of Oxford, was 70% effective. Inaccurate results based on the latest laboratory statements. On Wednesday November 25, AstraZeneca and the University of Oxford acknowledged a manufacturing error.

The statement comes as the company and the university discussed "very effective" injections, but did not explain why some study participants did not receive as much vaccine as initially expected. Inexplicably, the group of volunteers who received a lower dose of the product appeared to be better protected than the group who received two full doses.

90% efficiency?

In the low-dose group, AstraZeneca said the vaccine appeared to be 90% effective. In the group that received two full doses, the vaccine appeared to be 62% effective. By averaging, drug makers said the vaccine appeared to be 70% effective. A figure that attracts the experts: "You did two studies where different doses were used and you found a compound that does not represent any of the doses. I think a lot of people have problems with that," explains David Salisbury. and associate member of the Global Health Program at Chatham House Think Tank.

The partial results announced Monday come from large ongoing studies in the UK and Brazil to determine the optimal dose of the vaccine, as well as to examine safety and efficacy. In a statement, Oxford University reports that some of the vials used in the trial did not have the correct concentration of vaccine. Therefore, the participants received half a dose of the product. According to experts, the small number of people in the low-dose group makes it difficult to know if the observed efficacy is real. In detail, some 2,741 people received a half dose of the vaccine followed by a full dose, and a total of 8,895 people received two full doses.

As MedicalXpress points out, other data must be taken into account. In the low-dose group, no participant was older than 55 years. Younger people tend to develop a stronger immune response than older people.

At the moment, Oxford researchers are conducting new research to determine the effectiveness of a low dose. Soon, the details of the results will be officially released and will be communicated to UK health experts to decide whether or not to authorize the distribution of this vaccine.

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