BACK WHEN he was a reality-TV star, Donald Trump tweeted: “Healthy young child goes to doctor, gets pumped with massive shot of many vaccines…AUTISM.” More than 12 years later, on August 10th, Mr Trump acted on the thinking behind that dubious(可疑的，靠不住的) claim. A new executive order(行政命令) says the combined(联合的，组合的) measles, mumps and rubella vaccine should be split into three. It advises giving those and other jab(注射，接种)s at separate doctor visits. And it puts childhood vaccines into three bucket(类别，分类)s: those recommended for everyone (covering 11 diseases and infections, down from 18), those for high-risk groups and those to be decided on after talking to a doctor.
早在唐纳德·特朗普还是真人秀明星时，他就曾在推特上写道：“健康的孩子去看医生，被注射了大量疫苗……自闭症。”12多年后的8月10日，特朗普先生依据这一可疑说法背后的想法采取了行动。一项新的行政命令称，麻疹、腮腺炎和风疹联合疫苗应拆分为三种。该命令建议在分开的医生就诊时接种这些疫苗及其他疫苗。它还将儿童疫苗分为三类：推荐给所有人的疫苗（覆盖11种疾病和感染，低于此前的18种）、针对高风险群体的疫苗，以及在与医生商议后决定的疫苗。
There is no evidence that vaccines cause autism. Nor is there evidence that spreading out vaccines is beneficial.(也没有证据表明分开接种疫苗更有益。) In fact, doing so increases the window in which kids are vulnerable to infection. Doctors’ groups, therefore, lined up to denounce(谴责，公开抨击) the order. The head of the American Academy of Paediatrics called it “not only disheartening(令人沮丧的) but dangerous”. It puts “children’s health at risk”, said the boss of the American Medical Association.
没有证据表明疫苗会导致自闭症。也没有证据表明分开接种疫苗更有益。事实上，这样做会增加儿童易受感染的时间窗口。因此，医生团体纷纷站出来谴责这一命令。美国儿科学会主席称其“不仅令人沮丧，而且危险”。美国医学会负责人表示，这“将儿童的健康置于风险之中”。
The good news, then, is that Mr Trump’s order will have little practical(实际的，现实的) effect. States, not the federal government, normally set vaccination requirements for schoolchildren. And most of them are guided by abundant(大量的，丰富的) evidence that vaccines have driven down rates of infectious disease by a miraculous(奇迹般的) degree (see chart).
那么，好消息是特朗普先生的命令将几乎没有实际效果。各州而非联邦政府通常负责制定学龄儿童的疫苗接种要求。而且大多数州都以大量证据为指导，这些证据表明疫苗已将传染病的发病率降低到了惊人的程度（见图表）。