AstraZenecas The CEO told Bloomberg that the drug company is likely to conduct another global study on the effectiveness of its COVID-19 vaccine study after it became known that the more effective dosage in the existing Phase 3 clinical study was actually administered by mistake. AstraZeneca and its partner, Oxford University, reported interim results showing 62% efficacy for a full two-dose regimen and a 90% efficacy rate for half a dose followed by a full dose – which is what the scientists who did this Drug developed, later recognized actually only an accidental administration of two full doses.
This shouldn't dampen anyone's optimism about the Oxford / AstraZeneca vaccine. The results are still very promising, and an additional study is only being done to ensure that what was believed to be the result of the accidental half dosing is actually confirmed when the vaccine is deliberately administered this way. However, this could add to the time it takes for the Oxford vaccine to be approved in the US, as it will be done before a planned US study required by the FDA for domestic approval for domestic use.
According to AstraZeneca's CEO, the launch of the Oxford vaccine in the rest of the world is unlikely to be affected as the studies being conducted, including safety data, have already been conducted by participants from around the world outside the US.
While vaccine candidates from Moderna and Pfizer showed very strong efficacy even in early phase 3 data. Hopes for the AstraZeneca version are high as it is based on a different technology, can be stored and transported at standard refrigerator temperatures, and is not frozen, and costs a fraction per dose compared to the other two leading vaccines in development.
This makes it an incredibly valuable resource for global vaccination programs, including distribution, where cost and transportation infrastructures are paramount.