Investigators running the Oxford-AstraZeneca vaccine clinical trials expect an analysis within about two weeks on the jab's efficacy against the more transmissible strain initially detected in the U.K., a chief investigator said on a call on Wednesday.
"At this moment, we have an analysis on the way for the U.K. variant, which is B.1.1.7, which is both looking at neutralizing antibody data, which we hope will be completed within a few days and then submitted for publication to make that available to everyone," Prof. Andrew Pollard, director of the Oxford Vaccine Group and chief investigator of the Oxford vaccine trial, told an advisory panel for the Centers for Disease Control and Prevention (CDC).
Pollard said the strain has been dominant in the U.K. since the middle of December, due to rapid spread.
"We should be able to put together an analysis on efficacy against that probably by next week, and that is very much related to the ability to get sequence data," he continued. "That's the sort of timescale is within a week or two to have some data on the U.K. variant."
"In parallel, we’re also looking at neutralizing activity against the South African variant and there is certainly a possibility there in the trial to be able to look directly at efficacy against the South African variant, again it’s really taken off in the country since November, about 90% of the disease is thought to be caused by the new variant," Pollard said.
Previous data suggested AstraZeneca’s vaccine was safe and about 70% effective against COVID-19 disease. However, emerging strains involving mutations on the virus’ surface spike protein have sparked widespread concern. There was worry that changes in the protein, which the virus uses to infect healthy cells, could diminish efficacy among vaccines.
The U.S. has yet to authorize AstraZeneca’s vaccine, though it has seen emergency approval in the U.K. AstraZeneca has conducted clinical trials for its vaccine in the U.S., U.K., Brazil, Chile, Peru and South Africa.
"The trial sites in Brazil are not directly around the epicenter for the origin of the Brazil variant [called P.1] and so I don’t know at this moment know whether we’ll be able to make [a] direct comment about efficacy in Brazil," Pollard said.
The U.S. documented its first case of the Brazil P.1. variant on Monday in a Minnesota resident who had recent travel history to Brazil, health officials said.
"But we are working with the local teams on sequencing the virus from those individuals in the trial who have symptoms and also looking at neutralizing antibody against the virus and that will take a little bit longer because we’re just slightly behind on the sequencing."