Bregman D J, Langmuir A D
Department of Preventive Medicine, University of Southern California, Los Angeles 90033.
JAMA. 1990 Mar 16;263(11):1522-5.
Farr's Law of Epidemics, first promulgated in 1840 and resurrected by Brownlee in the early 1900s, states that epidemics tend to rise and fall in a roughly symmetrical pattern that can be approximated by a normal bell-shaped curve. We applied this simple law to the reported annual incidence of cases of acquired immunodeficiency syndrome in the United States from 1982 through 1987. The 6 years of incidence data closely fit a normal distribution that crests in late 1988 and then declines to a low point by the mid-1990s. The projected size of the epidemic falls in the range of 200 000 cases. A continuing incidence of endemic cases can be expected to emerge, but we believe it will occur at a low level.
法尔流行病定律于1840年首次公布，并在20世纪初由布朗利重新提出。该定律指出，流行病往往以大致对称的模式上升和下降，可用正态钟形曲线近似表示。我们将这一简单定律应用于1982年至1987年美国报告的获得性免疫缺陷综合征病例的年发病率。这6年的发病率数据与正态分布密切拟合，该分布在1988年末达到峰值，然后在20世纪90年代中期降至低点。预计该流行病的规模在20万例范围内。预计会出现地方性病例的持续发病率，但我们认为其发生率将处于低水平。
