Covid-19: What do we know about the late stage vaccine candidates?
Elisabeth Mahase
Abstract
Covid-19: What do we know about the late stage vaccine candidates?As some phase III trials of covid-19 vaccine candidates report early and unpublished results, Elisabeth Mahase summarises what we know so far Elisabeth Mahase University of Oxford and AstraZeneca vaccineThe ChAdOx1 nCoV-19 has been tested across the world, with trials starting in the UK and branching out to Brazil, South Africa, and the US.Phase II results, published in the Lancet, found that the vaccine produced a similar immune response in old and young participants.Phase III interim results, based on 131 cases, have been made available through a press release (23 November) and suggest the vaccine could be up to 90% effective when a half dose is given, followed by a full dose one month later. 1 When two full doses are given one month apart, however, the effectiveness drops to 62%.Sarah Gilbert-who is leading the vaccine team at the University of Oxford-said the half dose regime may be more effective because it "better mimics" a real infection.They are still, however, investigating this effect.