26 November 2020

Wired: “The AstraZeneca Covid Vaccine Data isn’t Up to Snuff”

The Oxford-AstraZeneca story is very different, though. Presumably, neither of the two trials from which they combined data could have provided a clear answer on the vaccine’s efficacy on its own. To make things worse, Oxford-AstraZeneca reported only the results for certain subgroups of people within each one. (For perspective on this: The two subgroups chosen leave out perhaps half the people in the Brazilian trial.) Meanwhile, one of their key claims is that giving half a dose of the vaccine on the first injection, followed by a standard dose on the second one, led to better outcomes—but neither of these trials had been designed to test this hypothesis. In fact, it’s since emerged that the half-dose/full-dose option started out as a mistake, and one that was only caught when some people in the study didn’t have the usual high rate of adverse effects.

Hilda Bastian

I had barely published my coronavirus update yesterday, when I saw a string of articles questioning the transparency and rigor of trials results for the vaccine jointly developed by AstraZeneca and the University of Oxford. Several of their decisions look problematic: they combined results from separate trials conducted in different countries with different methodologies, and it turns out the more successful trial, reportedly with 90% efficacy, did not include people over the age of 55, who are most at risk from this disease.

A diagram showing how the Oxford COVID-19 vaccine works
A diagram showing how the Oxford COVID-19 vaccine works. A chimpanzee adenovirus is used in the ChAdOx1 viral vector, engineered to match the SARS-CoV-2 spike protein.

It is regrettable, because of the three vaccine candidates in more advanced phases of testing, it was the cheapest, easier to manufacture and distribute. The best course of action would be for the company to start a fresh trial with proper dosage and analyze a clean set of results, even if it delays public availability. Approving this vaccine in the current state of testing would likely damage public trust in vaccination, and nobody can afford that at this critical time.

and apparently that is what the company is planning to do.

Post a Comment