OXFORD TRIALS | Regimen Has Average 70% Efficacy (Updated)

Race for the COVID-19 Vaccine.

November 23, 2020 (Updated Nov. 25)—The University of Oxford, in collaboration with AstraZeneca plc, today announced interim trial data from its Phase III trials.

The first report was that the average efficacy of the vaccine is 70 percent. The major advantage of the vaccine is that it can be much more cheaply produced than the other two vaccines in play from Pfizer and Moderna.

(Update: However, a New York Times raises questions about controls over the trials, in a setback for proponents of the vaccine.)

The AstraZeneca "candidate" vaccine (ChAdOx1 nCoV-2019) was shown to be effective at preventing COVID-19 (SARS-CoV-2) and offers a high level of protection. 

Phase 3 interim analysis including 131 Covid-19 cases indicates that the vaccine is 70 percent effective when combining data from two dosing regimens—90 percent in one and 62 percent in the other. The higher-efficacy regimen used a halved first dose and standard second dose. (Questions have been raised about the halved first dose, which appears to have been an unplanned underdose administered only to a group of subjects 55 and younger.)

Early indications are that the vaccine could reduce virus transmission, from an observed reduction in asymptomatic infections. There were no hospitalized or severe cases in anyone who received the vaccine. The vaccine was tested on a large safety database from over 24,000 volunteers from clinical trials in the UK, Brazil and South Africa, with follow up since April.

Crucially for the candidate vaccine, it can be easily administered in existing healthcare systems, stored at ‘fridge temperature’ (2-8 °C) and distributed using existing logistics. Also, large-scale manufacturing is ongoing in more than ten countries to support equitable global access.

For more information, go to the full announcement or the Oxford COVID-19 vaccine web hub or the COVID-19 trial website. (And the New York Times story previously  cited.)