Pharmaceutical giant AstraZeneca on Wednesday revised down the efficacy results of its COVID-19 vaccine in U.S. trials after health officials raised questions over the accuracy of its earlier admission.
In a release on Wednesday, the British-Swedish firm said its candidate vaccine AZD 1222 had an efficacy rate of 76% against symptomatic COVID-19 illness in its late-stage clinical trial.
The new results were a revision of a few percentage points from the 79% efficacy rate it said on Monday when it announced plans to apply for emergency use authorization from the Food and Drug Administration.
On Tuesday, U.S. health officials at the National Institute of Allergy and Infectious Disease said AstraZeneca had included “outdated information” in its efficacy results that “may have provided an incomplete view” of the data.
AstraZeneca admitted later that day to having used data based on “a pre-specific interim analysis” with a cut-off of Feb. 17, stating they would review the information and release new results within 24 hours.
In the report on Wednesday, AstraZeneca said high-level results of its late-stage trial “confirmed vaccine efficacy consistent with the pre-specified interim analysis” it announced earlier in the week.
It also said its vaccine had 100% efficacy against severe or critical disease and hospitalization and an 85% efficacy against symptomatic COVID-19 in patients over age 65.
