To answer that question, well look at what is in a MIC B12 shot besides B12
It acts as a shield, protecting you from external threats such as bacteria, viruses, and other harmful microorganisms
The Guideline, like other that have been written, sought to minimise the risk of cross infection to front line and ancillary health professionals who, as we all know, are risking their lives to help save others
These points come from official label language and vial-handling guidance, not from casual forum summaries
If you are taught to self-administer, use the route, needle size, site, and technique provided by your care team