Chapter 1: Introduction -- Part I: Scientifi Underpinnings, early expectations, and emerging challenges from the global inoculation experience -- Chapter 2: Appraisal of Some of the Key Postulates Underlying mRNA Vaccines -- Chapter 3: Relevance for mRNA vaccine safety -- Chapter 4: From Challenges to Opportunities and Open Questions -- Chapter 5: The challenge of evaluating vaccine safety and effectiveness -- Chapter 6: Safeguarding against the analog of antimicrobial-resistance development -- Chapter 7: Scales, pseudoscales, the human factor, and a way forward -- Part II: A deeper dive into mRNA vaccine safety and security, and developments until Delta -- Chapter 8: mRNA Vaccine safety and efficacy - official criteria when AEs are caused by the injection -- Chapter 9: mRNA Covid-19 vaccines best reflect effective pharmaceuticals - basic considerations and LNPs -- Chapter 10: mRNA Covid-19 pharmaceuticals and the spike antigen -- Chapter 11: Other facets of SARS-CoV-2 immunity, the risk of immune tolerance and T cell exhaustion -- Part III: The Omicron variants -- Chapter 12: Omicron -- Chapter 13: Conclusion.