AstraZeneca released new data Thursday from its Phase III trial of AZD1222 that report its vaccine was 76% effective at overall prevention of symptomatic COVID-19, 85% effective in adults 65 and older, and 100% effective in preventing severe or critical disease and hospitalization.
On Monday, the company released data showing its SARS-CoV-2 vaccine was 79% effective at preventing symptomatic COVID-19 and 100% effective at preventing severe disease and hospitalization. Following that announcement, an independent Data and Safety Monitoring Board (DSMB) notified NIAID, BARDA, and AstraZeneca that it was concerned the company may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data.
AstraZeneca says the latest analysis of results released Thursday confirm its vaccine efficacy was consistent with the pre-specified interim analysis announced on Monday March 22, 2021 and these results have been presented to the independent Data Safety Monitoring Board.
This primary efficacy analysis included the accrual of 190 symptomatic cases of COVID-19 from the 32,449 trial participants, an additional 49 cases to the previously announced interim analysis. Participants were randomised on a 2:1 ratio between the vaccine and placebo group.
The primary endpoint, vaccine efficacy at preventing symptomatic COVID-19 was 76% (confidence interval (CI): 68% to 82%) occurring 15 days or more after receiving two doses given four weeks apart. In addition, results were comparable across age groups, with vaccine efficacy of 85% (CI: 58% to 95%) in adults 65 years and older. A key secondary endpoint, preventing severe or critical disease and hospitalisation, demonstrated 100% efficacy. There were eight cases of severe COVID-19 observed in the primary analysis with all of those cases in the placebo group.
The vaccine was well tolerated, and no safety concerns related to the vaccine were identified, the company reported.
The primary analysis is pre-specified in the protocol and will be the basis for a regulatory submission for Emergency Use Authorization to the US Food and Drug Administration in the coming weeks.
Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D, said: “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. 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.”