Topline
Peer reviewed data published Tuesday in The Lancet medical journal show that the Covid-19 vaccine developed by AstraZeneca and the University of Oxford is safe, well tolerated and capable of preventing disease, though just how capable is unknown as crucial questions surrounding dosage remain unanswered, with one dosing regime inducing a competitive 90% efficacy, and another regime coming in as low as 62%.
AstraZeneca and Oxford released interim analysis for their Covid-19 vaccine trial in the Lancet ... [+]
Key Facts
Adding necessary detail to an earlier press release, The Lancet paper, assessed by independent scientists, shows the interim results for advanced clinical trials of nearly 12,000 people.
The results show the vaccine to be “safe and effective at preventing symptomatic Covid-19” and “protects against severe disease and hospitalization.”
While researchers state the vaccine to be 70% effective at preventing disease, this is not a figure that would be borne out in real life, as it was derived from the average efficacy of two different dosing regimens.
When given as two full doses, the data show the vaccine to be 62% effective at preventing disease, with this figure rising to 90% when given as a half dose followed by a full dose, a phenomenon the researchers acknowledge they do not fully understand, saying it “will require further research as more data becomes available.”
AstraZeneca CEO Pascal Soriot said the company had already started submitting data to regulatory authorities around the world for early approval, and that the company’s “global supply chains are up and running, ready to quickly begin delivering hundreds of millions of doses on a global scale at no profit.”
Regulators would likely accept a less-efficacious vaccine (the FDA indicated they would accept 50%), which is still of value, especially in a cheaper, less difficult to store vaccine like Oxford-AstraZeneca’s, which is a source of hope for many less affluent nations.
Key Background
The announcement by Oxford and AstraZeneca comes on the same day that vaccination began in earnest in the U.K., which approved the vaccine developed by Pfizer and BioNTech last Wednesday, which reports 95% effectiveness, and comes on the heels of regulatory submissions from Moderna, who also report 95% effectiveness. With those figures in mind, and the considerable degree of uncertainty in AstraZeneca's results, one would be forgiven for feeling less optimistic about the groups’ achievements.
What We Don’t Know
More work will be needed to shore up today’s reported findings. It’s not known why, for instance, the different dosing regimens result in such different degrees of protection or even if such higher levels of protection hold true in more extensive studies (the numbers reported are relatively low). The findings for the most promising dosing regimen also do not include older participants (55 or over), a key demographic in need of protection, though earlier studies do show a “robust” immune response in older adults.
Further Reading
AstraZeneca-Oxford Vaccine Up To 90% Effective At Preventing Covid-19, Early Results Show (Forbes)
Oxford Covid-19 Vaccine Induces ‘Robust’ Immune Response In Older Adults, Early Findings Show (Forbes)
‘V-Day’: U.K. Kicks Off Western World’s First Covid-19 Vaccination Campaign (Forbes)
Here’s Why The U.K. Beat The U.S. To Approve A Covid-19 Vaccine For Emergency Use (Forbes)
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