MMWR Morb Mortal Wkly Rep. 1999 Jul 30;48(29):621-9.
Deaths from infectious diseases have declined markedly in the United States during the 20th century. This decline contributed to a sharp drop in infant and child mortality and to the 29.2-year increase in life expectancy. In 1900, 30.4% of all deaths occurred among children aged <5 years; in 1997, that percentage was only 1.4%. In 1900, the three leading causes of death were pneumonia, tuberculosis (TB), and diarrhea and enteritis, which (together with diphtheria) caused one third of all deaths. Of these deaths, 40% were among children aged <5 years. In 1997, heart disease and cancers accounted for 54.7% of all deaths, with 4.5% attributable to pneumonia, influenza, and human immunodeficiency virus (HIV) infection. Despite this overall progress, one of the most devastating epidemics in human history occurred during the 20th century: the 1918 influenza pandemic that resulted in 20 million deaths, including 500,000 in the United States, in <1 year-more than have died in as short a time during any war or famine in the world. HIV infection, first recognized in 1981, has caused a pandemic that is still in progress, affecting 33 million people and causing an estimated 13.9 million deaths. These episodes illustrate the volatility of infectious disease death rates and the unpredictability of disease emergence.
20世纪期间，美国传染病导致的死亡人数显著下降。这一下降促成了婴幼儿死亡率的急剧下降以及预期寿命延长29.2岁。1900年，所有死亡病例中有30.4%发生在5岁以下儿童中；1997年，这一比例仅为1.4%。1900年，三大主要死因是肺炎、结核病和腹泻及肠炎，这些疾病（连同白喉）导致了三分之一的死亡。在这些死亡病例中，40%发生在5岁以下儿童中。1997年，心脏病和癌症占所有死亡病例的54.7%，肺炎、流感和人类免疫缺陷病毒（HIV）感染导致的死亡占4.5%。尽管取得了这一总体进展，但人类历史上最具毁灭性的流行病之一发生在20世纪：1918年的流感大流行在不到1年的时间里导致2000万人死亡，其中在美国有50万人死亡——这比世界上任何一场战争或饥荒在如此短的时间内造成的死亡人数都要多。1981年首次确认的HIV感染引发了一场仍在蔓延的大流行，影响了3300万人，估计造成1390万人死亡。这些事件说明了传染病死亡率的波动以及疾病出现的不可预测性。
