AstraZeneca Reports Up-to-Date COVID-19 Vaccine Efficacy Results


The updated analyses of the AZD1222 COVID-19 vaccine will be submitted to the FDA for emergency use authorization, according to AstraZeneca.

Covid vaccines

AstraZeneca published an up-to-date analysis on Thursday of its phase 3 COVID-19 vaccine clinical trial data for AZD1222, overturning earlier data that was announced on Monday.

The latest data release is the latest development amid recent concerns from the Data and Safety Monitoring Board (DSMB) regarding the clinical trial results published earlier this week. The DSMB issued concerns that the pharmaceutical company included outdated information in their clinical trial interim data. The pharmaceutical company responded by clarifying that the data stemmed from a study period that ended data collection on February 17.

Related: Independent Review Board Shares Concerns Over Outdated Data in AstraZeneca COVID-19 Clinical Trial

The news follows a flurry of temporary suspensions of the COVID-19 vaccine in several European countries due to reports of rare, but serious, blood clots.

The latest analysis showed 76% vaccine efficacy against symptomatic COVID-19 (CI: 68% to 82%) 15 days or more after receiving 2 doses, which were given 4 weeks apart; interim data announced on Monday reported a 79% efficacy rate.

In addition, the data pointed to 100% efficacy in 8 study participants against severe or critical disease and hospitalization and 85% efficacy (CI: 58% to 95%) against symptomatic COVID-19 in patients over the age of 65. Although previous data also demonstrated 100% efficacy for severe or critical infection, the numbers from Monday’s report claimed 80% efficacy in patients over 65.

The analysis included 49 more symptomatic COVID-19 cases than Monday’s interim analysis, for a total 190 symptomatic cases of COVID-19 out of 32,449 trial participants. The vaccine candidate was well-tolerated, with no safety concerns identified for the vaccine, according to the news release.

AstraZeneca is now preparing to submit an emergency use authorization to the FDA in the coming weeks.

“The primary analysis is consistent with our previously released interim analysis and confirms that our COVID-19 vaccine is highly effective in adults, including those aged 65 years and over,” said Mene Pangalos, executive vice president, BioPharmaceuticals R&D. “We look forward to filing our regulatory submission for Emergency Use Authorization in the US and preparing for the rollout of millions of doses across America.”


  1. AZD1222 US Phase III primary analysis confirms safety and efficacy. News Release. AstraZeneca; March 25, 2021. Accessed March 25, 2021.

Related Videos
© 2024 MJH Life Sciences

All rights reserved.