Doubts raised over AstraZeneca-Oxford vaccine data

Disquiet is growing over the way that Oxford university and AstraZeneca have handled the early readout from trials of their coronavirus vaccine, which much of the developing world may rely on to emerge from the pandemic. The results were hailed a success for showing an average efficacy of 70 per cent — a figure reached by pooling the results from cohorts on two different dosing regimens. One set of participants received two identical doses a month apart, while the other group received a half-dose, and then a full dose. The efficacy for the first, larger group was 62 per cent. In the second subgroup, it was 90 per cent. It has emerged that administration of the half-dose started with a mistake. It was then given to a smaller number of participants than those who received two full doses, making the discovery of its greater effectiveness look like a lucky break.