AstraZeneca/Oxford COVID-19 Vaccine Candidate Third to Show Promise

November 23, 2020
Grace Halsey

The AstraZeneca/Oxford vaccine candidate showed 90% efficacy in one dosing regimen; 62% in a second; and an average efficacy rate of 70%.

AstraZeneca and Oxford University today announced that the partnership’s COVID-19 vaccine candidate AZD 1222 had achieved efficacy of 90% using 1 of 2 dosing regimens tested.

The 90% efficacy was seen among participants when the vaccine was given first as a half dose followed by a full dose given at least one month later. The second regimen gave the vaccine as 2 full doses, one month apart, after which the vaccine showed 62% efficacy. Combined analysis from both dosing regimens resulted in an average efficacy of 70%.

The high-level results from an interim analysis of ongoing AZD 1222 clinical trials in the UK and Brazil found the vaccine highly effective in preventing COVID-19, the primary endpoint, and no hospitalizations or severe cases of disease were reported among participants.

“These findings show that we have an effective vaccine that will save many lives. Excitingly, we’ve found that one of our dosing regimens may be around 90% effective and if this dosing regime is used, more people could be vaccinated with planned vaccine supply," said Professor Andrew Pollard, Chief Investigator of the Oxford Vaccine Trial at Oxford.

An independent Data Safety Monitoring Board determined that the analysis met its primary endpoint showing protection from COVID-19 occurring 14 days or more after receiving 2 doses of the vaccine. No vaccine-related safety events have been confirmed and the vaccine was well tolerated in both dosing scenarios.

“Today marks an important milestone in our fight against the pandemic. This vaccine’s efficacy and safety confirm that it will be highly effective against COVID-19 and will have an immediate impact on this public health emergency,” said AstraZeneca CEO pascal Soriot. “Furthermore, the vaccine’s simple supply chain and our no-profit pledge and commitment to broad, equitable and timely access means it will be affordable and globally available, supplying hundreds of millions of doses on approval.”

The announcement comes just several days after Pfizer and BioNTech submitted a request to the US Food and Drug Administration for emergency use authorization (EUA) for their COVID-19 vaccine candidate, BNT162b2. The companies announced on November 18, 2020 that the vaccine showed 95% efficacy in participants not previously infected with COVID-19 and also in those with and without prior infection, beginning 28 days after the first dose which meets all of the study’s primary efficacy standpoints.

Moderna on November 16, 2020, announced that the vaccine candidate mRNA-1273 showed an efficacy rate of 94.5% in a phase 3 trial and said the company will seek EUA in the coming weeks.


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