UK's routine childhood immunisation programme
1. Where two or more injections are required at the same time, these should ideally be given in different limbs. Where this is not possible, injections in the same limb should be given at least 2.5cm apart.
2. Where injections can only be given in two limbs, it is recommended that the MMR, as the vaccine least likely to cause local reactions, is given in the same limb as the MenB with the PCV and Hib/MenC boosters given into the other limb
- The Green Book. Chapter 11 - The UK immunisation schedule (April 2019)