Oxford/AZ Vaccine Efficacy Data: What was announced today is that they have quite different results for two different dosing regimens. This interim analysis was run when 131 cases had been accrued across trials in the UK, Brazil, and South Africa across about 24,000 trial participants (treatment and control groups). In the treatment group, 8,895 participants received two full doses of the vaccine, spaced one month apart, and 2,741 patients got a half dose at first, followed by a full dose a month later. And the efficacy rates for these two dosing regimes were very different: 62% for the two-full-dose group and 90% for the half/full group. I do not see a breakdown of how those 131 cases partitioned across the two groups, but the overall N has to be higher for the first, doesn’t it? I’d like to know what the statistics are for the 90% efficacy number, for sure.
Why might there be such a significant split in efficacy?
Dosing error turns into lucky punch for AstraZeneca and Oxford: A stroke of good fortune from a dosing error will pave the way for AstraZeneca and Oxford University to submit their COVID-19 vaccine for regulatory clearance.
The British drugmaker said on Monday that the vaccine could be around 90% effective, when administered as a half dose followed by a full dose a month later, citing data from late-stage trials in Britain and Brazil.
