The following dose interval is recommended for each of the vaccines for the primary vaccination course:
Pfizer in adults- 8 weeks apart (minimum 3 weeks apart)
Pfizer paediatric formulation – 8 weeks apart (but can be done 3 weeks apart under special circumstances)
Moderna- 8 weeks apart (minmum 4 weeks apart)
Astra Zeneca – 3 months apart but can be done as short as 6 weeks apart
Some patients who have severe immunosuppression require three doses to complete their “primary immunisation”. This is approved for use for patients with certain conditions in accordance with strict criteria.  Dose 3 is given 2 months after the 2nd dose. Patients who require 3 doses for their primary immunisation are also eligible for further booster doses as outlined below.