A scientist overseeing COVID-19 vaccine trials expects a large US study to determine how effective AstraZeneca's experimental inoculation is, following confusing data from other trials released by the company and its partner Oxford University, as reported in This is Money.
"We feel very comfortable that we designed a really good trial in the US, where everybody's getting boosted in a uniform time, and we know what the dose is," said Larry Corey, co-leader of the US Coronavirus Vaccine Prevention Network, who helped design and is overseeing trials for the US government's Operation Warp Speed program.
Late last month, AstraZeneca released interim data from trials in the UK and Brazil showing a vastly divergent performance when its vaccine, AZD1222, was tested in two different dose combinations.
According to AstraZeneca, a small group of trial volunteers inadvertently received a half dose followed by a full dose, instead of the planned two full doses. In that group, the vaccine proved to be 90% effective at preventing illness, but the larger group that received two full doses showed a 62% success rate.
The dosing in the UK trial "wasn't done correctly," Corey maintains, although he acknowledged that the dosing difference does not fully explain the variation in effectiveness seen in the UK and Brazilian trials.
"With the Oxford data…there's a lot of lack of uniformity in the schedule and the dose that makes interpretation of the results difficult at best," he said, but "my personal summation is that there seems to be effectiveness in [AZD1222] from this other trial that provides optimism that the current trial in the US will define that effectiveness."
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