“发病率”和“患病率”
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“发病率”对应的英文是 “incidence rate”，表示在一定期间内，一定人群中某病
新病例
出现的频率。发病率 = 一定期间内某人群中某病新病例数/同时期暴露人口数。“发病率”的分母是有发病危险的人口数 (population at risk)。(The incidence of disease is the number of new cases occurring in a population over a defined time interval.)
“患病率”对应的英文是“prevalence rate”，也称“现患率”，指特定时间内总人口中某病 新旧病例 所占比例。患病率 = 某观察期间一定人群中现患某病的新旧病例数/同期的平均人口数（被观察人数）。(Prevalence is a measure of the number of total cases of a disease in a population at a certain moment in time.)
ncidence measures how quickly one sees new cases of infection or disease, whereas prevalence describes how many people total in a population are affected, regardless of when they become infected or sick.
