British pharmaceutical company AstraZeneca and Oxford University have published Phase 3 trial data showing strong efficacy for their coronavirus vaccine in a peer-reviewed medical journal. They are the first coronavirus vaccine makers to do so.
The results, published in the Lancet, confirm that the vaccine is about 70% effective. However, that figure is the average of two different groups receiving different doses. The vaccine showed an efficacy of 62% among the group of participants who received two standard doses. Another group accidentally received a small dose at first and then later received a full dose. Among those, the vaccine was 90% effective.
However, the second group had just only 2,700 participants, which is too small to prove such high efficacy. Scientists at AstraZeneca and Oxford said that the trials are ongoing.
Some scientists argue that the 70% efficacy number is meaningless.
“We are now all familiar with the vaccine efficacy results from the low-dose (90 percent) vs. standard-dose (62 percent) regimens, which are quite different,” Julian Tang, a clinical virologist at the University of Leicester, told the Washington Post. “The combined efficacy of 70 percent doesn’t actually matter as when it comes down to it, you will get one or the other dosing regimen with that particular efficacy — though it may take a while before the low-dose regimen is potentially approved.”
