1 From the Finnish Institute for Health and Welfare, Helsinki (H.N.); and the Institute of Preventive and Social Medicine, University of Bern, Bern, Switzerland (A.W.-S.). Dr. Nohynek serves as chair of the World Health Organization (WHO) Strategic Advisory Group of Experts (SAGE) Working Group for Covid-19 vaccines and as the secretary of the National Immunization Technical Advisory Group of the Finnish Institute for Health and Welfare, and Dr. Wilder-Smith serves as coordinator for the WHO SAGE Working Group for Covid-19 vaccines.