AstraZeneca's COVID-19 vaccine 70% effective, shares fall

AstraZeneca’s COVID-19 vaccine has achieved 70% efficacy in a late-phase analysis. The 70% figure is an average that masks variation in the performance of two dosing regimens, one of which was found to be 90% effective.

With the Pfizer-BioNTech and Moderna vaccines achieving efficacy of around 94%, the bar was set high for AstraZeneca’s AZD1222. Overall, the COVID-19 vaccine, which AstraZeneca is developing with the University of Oxford, fell well short of that bar. Yet, the details offer encouragement that the vaccine can be highly effective and more broadly adopted than the other candidates.