• Thu. Sep 22nd, 2022

A COVID-19 vaccine developed by the UK’s Oxford University and AstraZeneca has an average efficacy of 70 percent. Efficacy rose rose to 90 percent when the vaccine was given first as a half dose, and then as a full dose.

Nov 23, 2020

More effective when a lower dose used
Illustration by Alex Castro / The Verge
A COVID-19 vaccine developed by the UKs Oxford University and AstraZeneca has an average efficacy of 70.4 percent, according to interim analysis announced today. In trials, the vaccines effectiveness varied depending on the dose amounts given. When two full doses were given a month apart the effectiveness stood at 62 percent, but this rose to 90 percent when the vaccine was given first as a half dose, and then as a full dose.
The announcement follows promising early results from vaccines developed by Pfizer and BioNTech, and Moderna, which both appear to have slightly higher 95 percent efficacy rates. However, according to BBC News, the Oxford vaccine has the advantage of being cheaper and easy to store, since it can be transported and handled at normal refrigerated temperatures. The Pfizer vaccine needs to be stored at -70 degrees Celsius (-94 degrees Fahrenheit). The Food and Drug Administration (FDA) previously said vaccines would be required to be at least 50 percent effective to gain its approval.
The Oxford vaccine trial involved over 23,000 participants in the UK and Brazil. Of the participants who received the vaccine, 30 developed COVID-19, compared to 101 participants who received the placebo, BBC News reports. There were no hospitalizations or severe COVID-19 cases among participants who received the vaccine, AstraZeneca says.
Were really pleased with these results, the trials lead investigator Professor Andrew Pollard told the BBC. He added that the higher effectiveness rate for the initial half dose potentially means that therell be a lot more doses to distribute.
With this latest round of trials complete, the team are preparing to submit the vaccine for regulatory approval. If approved, AstraZeneca hopes to to manufacture three billion doses of the vaccine to distribute worldwide. The Guardian reports a rollout could begin in weeks.
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