Publications

While there is consensus for the use of personal protective equipment and other measures for the prevention of transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in high-risk situations, such as aerosol-generating medical procedures, there is a divergence of opinion and enthusiasm for measures such as social distancing, cloth masks, and other recommendations in low-risk situations. The insights of epidemiologist Geoffrey Rose¹ on sick and high-risk populations may be helpful. In its simplest form, his concept can be explained as follows: the high-risk subpopulation—such as elderly people with preexisting cardiac or pulmonary conditions—may contribute a lesser share to the outcome (eg, infection, death) than a low-risk subpopulation would. This is simply because of the sheer larger number of persons in the low-risk subpopulation. Consider, for example, a population of 1,000 persons, with 100 in a high-risk subpopulation and 900 in a low-risk subpopulation, and a rate of infection 4 times as high in the high-risk subpopulation as in the low-risk subpopulation; their rates of infection are 20% and 5%, respectively. In this hypothetical scenario, the high-risk subpopulation contributes 20 cases to the outcome compared to 45 cases from the low-risk subpopulation.