The article in the link below explains the rationale behind the different Groups (1 through to 15) who will receive the vaccine.
It also explains that within Group 3 (70 years and over), it will be the 85 years and over who get the vaccine first as this group of people are at higher risk of hospitalisation and death.
The article in the link below gives information about the Covid 19 vaccine
link to getting your Covid 19 vaccine