This second fully updated and extended edition of the textbook serves as a highly readable guide on latest developments in vaccine development and vaccination programs in infants, children and adolescents from a European perspective. The first part of the book introduces to general vaccinology, immunization programs and formulation, effects and unwanted effects of vaccines. The second and third part provide an overview on current viral and bacterial vaccines. The fourth and last part of this book discusses new vaccines in the pipeline and gives insights into safety and regulatory matters. This second edition is extended by a whole new chapter on COVID-19 vaccines. This book serves as a reference textbook in the field and helps to standardize the information on vaccines and immunization programs in the WHO European Region.