By late 2021, the COVID pandemic has become one of the most serious infectious diseases of recent years. Only the influenza pandemic of 1918 and the AIDS pandemic which has persisted since the early 1980s have had similar intensities universally. The viruses responsible for the three diseases are distinctly different and the responses of the medical communities have also differed and depended to a large extent on advances in technology. I will describe how these advances have developed since 1918, how they have combined to inform current public health responses and how they might influence medical practice and research in the future.