AstraZeneca COVID-19 vaccine safe and effective, studies suggest

Studies on the COVID-19 vaccine candidate from AstraZeneca and Oxford University suggest that it is safe and about 70 percent effective on average, though some questions remain.

The partial results published in The Lancet on Tuesday confirmed that the two full doses given at least one month apart appeared to be 62 percent effective, while a half dose followed by a full dose was about 90 percent effective.

AstraZeneca and Oxford first announced the efficacy results of their vaccine late last month. The findings later came under scrutiny after the company acknowledged that members of a sub-group of trial participants were originally mistakenly given a half dose followed by a full dose.

The admission, along with a relatively small test group compared to other studies, drew questions among experts on the accuracy of the findings.

The Lancet’s interim analysis published Tuesday focused on studies of the vaccine in the U.K., Brazil and South Africa, with efficacy data on 11,636 participants reported.