The adenovirus-based vector vaccine for COVID produced by AstraZeneca is based on research conducted by the University of Oxford. Despite questions as to the most efficacious dose level and the interval between primer and booster, the product was approved by the U.K. Joint Committee on Vaccination and Immunization.

Although the AstraZeneca vaccine did not achieve the +90 percent level of protection in Phase-3 trials as the mRNA vaccines produced by Pfizer and Moderna, authorities allowed provisional registration based on a modification of the dose schedule. The second dose will be administered close to twelve weeks after the initial priming vaccination.

Advantages of the AstraZeneca vaccine involve low cost, possibly in the region of $3 per dose, and ease of storage, transport and handling since the vaccine will be held at conventional refrigeration temperature.

The decision to deploy the vaccine was in part based on the ascending incidence rate in the UK possibly associated with the variant that is apparently more infectious.  A second motivation is to have the vaccine available for developing nations especially in Africa where it has been successfully tested. There is a great need to protect populations in high-density areas with minimal health resources.

Dr. Andrew Pollard of Oxford University characterized the vaccine of which he was one of the developers as "a vaccine for the world".  AstraZeneca indicated that it would have up to three billion doses available by the end of 2021.  It is intended to track the response of recipients and adjust dosing regimens as indicated by results.