The Oxford-AstraZeneca vaccine is being manufactured locally by the Serum Institute of India, the world’s largest vaccine manufacturer. It says it is producing more than 50 million doses a month.

The jab is administered in two doses given between four and 12 weeks apart. It can be safely stored at temperatures of 2C to 8C, about the same as a domestic refrigerator, and can be delivered in existing health care settings such as doctors’ surgeries. 

The jab developed by Pfizer-BioNTech, which is currently being administered in several countries, must be stored at -70C and can only be moved a limited number of times – a particular challenge in India, where summer temperatures can reach 50C.

International clinical trials of the Oxford-AstraZeneca vaccine showed that when people were given a half dose and then a full dose, effectiveness hit 90%.