The global COVID-19 pandemic has provided a dramatic, face-to-face demonstration of both the power and limitations of molecular medicine and epidemiology. The rapid development of highly effective vaccines was made possible by the adaptation of novel RNA-based approaches in which the patient's immune response is activated via the endogenous expression of genetically-encoded antigens, rather than the physical injection of a non-infectious antigen. Utilizing the patient's own cells as the bioreactor for generating antigens, rather than some animal or culture, enabled scientists to use the self-amplifying capacity of polynucleotides to accelerate both the speed of vaccine development and subsequent large-scale manufacture. The illustration on the cover of the thirty-second edition depicts a neutralizing antibody, in blue, bound to the spike protein on the surface of the SARS-CoV-2 coronavirus, better known as COVID-19, which is shown in red. The epitope to which the antibody binds overlaps that at which the virus binds to the ACE-2 receptor, the membrane protein by which the pathogen recognizes, binds to, and subsequently invades human cells. Therapeutic antibodies thus protect by physically blocking association of the Spike protein with the ACE-2 receptor.