This thesis explores the pharmacology of COVID-19 vaccines, focusing on their mechanisms of action, pharmacokinetics, and pharmacodynamics. It provides a comparative overview of major vaccine platforms—including mRNA, viral vector, and protein subunit vaccines—with special emphasis on those approved in the European Union. The work highlights how these vaccines induce both humoral and cellular immunity, contributing to long-term protection against SARS-CoV-2. It also addresses rare but notable adverse effects, balanced against the overwhelming clinical benefits observed globally. The thesis highlights the pivotal role of mRNA technology in vaccinology and its potential for future applications in the prevention of infectious diseases.