62% is very disappointing - particularly when the other vaccines are 90%.Oxford-AstraZeneca vaccine approved but as a 2 full dose vaccine - 62% success. The smaller dose followed by a larger dose has not been approved yet as not enough data.
Reports suggesting that it will be deployed as a single dose first to as many as possible with 2nd dose coming 12 weeks later. It is believed that leaving a larger gap between the doses increases its effectiveness.