To determine if there are sex differences in susceptibility to infection would require an unethical experiment:expose 1,000 otherwise similar men and women to the virus and see who gets sick.

　　要确定对感染的易感性是否存在性别差异，需要进行一项不道德的实验:让1000名身体情况相似的男性和女性接触这种病毒，然后看看谁会得病。

　　The difference is fatality rates,however,is real:1.7%for women and 2.8%for men,China CDC reported.

　　然而，中国疾病预防控制中心的报告显示，致死率的差别是真实存在的:女性为1.7%，男性为2.8%。

　　Sick or healthy

　　已患其他疾病和健康者的比较

　　The male-female difference in fatality rates,and perhaps in reported incidence,may arise from differences in underlying health.People with pre-existing illness are more likely to get seriously ill from Covid-19,and men have a higher incidence of such chronic illnesses as cardiovascular disease.

　　死亡率和报告发病率的男女差异可能源于基本健康状况的差异。患有既往疾病的人更容易因Covid-19而发展为重症，男性罹患诸如心血管疾病等慢性疾病的重症几率更高。

　　In the first large study of the effect of underlying illness,researchers in China analyzed 1,590 patients from throughout the country with laboratory-confirmed disease.They calculated how“co-morbidities”—existing illnesses—affected the risk of being admitted to intensive care,being put on a ventilator,or dying.

　　在对潜在疾病影响的第一项大型研究中，中国的研究人员分析了来自全国各地的1,590名确诊的患者。他们计算了“并发症”(即现有疾病)如何影响接受重症监护，使用呼吸机或死亡的概率。

　　After taking into account the patients'ages and smoking status,the researchers found that the 399 patients with at least one additional disease(including cardiovascular diseases,diabetes,hepatitis B,chronic obstructive pulmonary disease,chronic kidney diseases,and cancer)had a 79%greater chance of requiring intensive care or a respirator or both,or of dying,they reported last week in a paper posted to medRxiv,a preprint site that posts research before it has been peer-reviewed.The 130 with two or more additional diseases had 2.5 times the risk of any of those outcomes.

　　在考虑了患者的年龄和吸烟情况后，研究人员上周在medRxiv网站上发表了一篇论文，称他们发现，399名至少有一种额外疾病(包括心血管疾病、糖尿病、乙型肝炎、慢性阻塞性肺病、慢性肾病和癌症)的患者需要重症监护或使用呼吸器或两者都需要，或死亡的几率要高出79%。患有两种或两种以上附加疾病的130名患者发生上述任何一种结果的风险是2.5倍。

　　That fits with what's known about other respiratory viruses.People with a single co-morbidity who catch avian flu(H7N9)are 3.4 times more likely than otherwise-healthy flu patients to require ventilators and other intensive care.SARS and MERS,which are also caused by coronaviruses,are more severe in patients with underlying illnesses,too.

　　这与我们对其他呼吸道病毒的了解相符。与其他健康的流感患者相比，感染H7N9的单一合并病患者需要呼吸器和其他重症护理的可能性高3.4倍。由冠状病毒引起的SARS和中东呼吸综合征(MERS)对有潜在疾病的患者也更为严重。

　　Breaking down the Covid-19 risk with the most common co-morbidities,the scientists found that cancer raises the risk 3.5-fold,COPD 2.6-fold,and diabetes and hypertension by about 60%.Because it isn't unusual for someone to have an underlying disease(especially diabetes and hypertension)but not know it,the last figure is likely an underestimate.

　　以最常见的并发症来分解Covid-19风险后，科学家发现癌症将风险提高了3.5倍，COPD提高了2.6倍，糖尿病和高血压的风险提高了约60%。由于某人患有其他疾病(尤其是糖尿病和高血压)，但并不知道，因此最后的数字可能被低估了。

　　Co-morbidities also raise the risk of dying from Covid-19.China CDC's analysis of 44,672 patients found that the fatality rate in patients who reported no other health conditions was 0.9%.It was 10.5%for those with cardiovascular disease,7.3%for those with diabetes,6.3%for people with chronic respiratory diseases such as COPD,6.0%for people with hypertension,and 5.6%for those with cancer.

　　并发症也增加了死于Covid-19的风险。中国疾病预防控制中心对44672例患者的分析发现，未报告其他健康状况的患者的死亡率为0.9%。患有心血管疾病的人占10.5%，患有糖尿病的人占7.3%，患有慢性阻塞性肺病等慢性呼吸道疾病的人占6.3%，患有高血压的人占6.0%，患有癌症的人占5.6%。

　　Underlying disease might change the course of Covid-19.During the height of the epidemic in Wuhan,37 of 230 patients receiving dialysis for kidney failure at Remnin Hospital developed the disease.Even though none were sick enough to require intensive care or a mechanical ventilator,six of them died,for a very high fatality rate of 16%.Oddly,however,none of the six died of pneumonia,Remnin researchers reported.Instead,the causes of death were heart disease,stroke,and high blood levels of potassium(a result of kidney failure).The high fatality rate of Covid-19 in already-sick people might result not from the virus but from an exacerbation of existing disease.

　　潜在疾病可能会改变Covid-19的病程。在武汉疫情高峰期间，武汉人民医院接受肾衰竭透析的230名患者中有37名患上了这种疾病。即使没有人病到需要重症监护或使用机械呼吸机，也有6人死亡，死亡率高达16%。不过，人民医院研究人员报告说，奇怪的是，这六人中没有一个人死于肺炎。相反，死亡原因是心脏病，中风和高血钾水平(肾衰竭的结果)。已经患病的人中Covid-19的高死亡率可能不是由于病毒引起的，而是由于现有疾病的加剧而引起的。

　　About 60%of U.S.adults have at least one underlying health condition,Tom Frieden,former director of the U.S.Centers for Disease Control and Prevention,told reporters on Monday.

　　美国疾病控制与预防中心前主任Tom Frieden周一对记者说，大约60%的美国成年人患有至少一种潜在疾病。

　　Pregnancy

　　怀孕带来的影响

　　In early February,Chinese state media reported that a woman infected with the virus gave birth to a baby who later tested positive for it.Newborns might become infected because of close proximity to a patient,like anyone else,but the case raised fears that a pregnant woman can transmit the virus to her fetus via the placenta.

　　2月初，中国官方媒体报道说，一名感染该病毒的妇女生了一个婴儿，后来对其进行了阳性检测。新生儿可能会因为与其他患者一样靠近患者而被感染，但此案使人们担心孕妇会通过胎盘将病毒传播给胎儿。

　　Only one small study has investigated such“vertical transmission.”Scientists at Wuhan University found that,of nine pregnant patients infected with the virus(all had a caesarean section)in their third trimester,none seemed to pass the virus to their babies,all of whom scored at the top of the Apgar scale of newborn health.

　　只有一项小型研究调查了这种“垂直传播”。武汉大学的科学家们发现，在9名妊娠晚期感染病毒的孕妇中(所有人都进行了剖腹产)，似乎没有人将病毒传给他们的婴儿，他们的新生儿健康评分都排在阿普加(Apgar)量表的前列。

　　As for the mothers,“Covid-19 seems not to be especially severe in pregnant women,at least based on the small number in this study,”the scientists wrote.That was somewhat surprising because pregnancy suppresses the immune system(so it doesn't attack the fetus);pregnant women are more susceptible to respiratory pathogens than non-pregnant women.Nevertheless,none of the nine women developed severe Covid-19 pneumonia.

　　至于母亲，“Covid-19似乎在孕妇中并不特别严重，至少根据这项研究中的少量数据，”科学家写道。这有点令人惊讶，因为怀孕会抑制免疫系统(所以它不会攻击胎儿);孕妇比非孕妇更容易感染呼吸道病原体。然而，这9名妇女均未出现严重的Covid-19肺炎。

　　It may be that immuno-suppression is actually helpful.Some of the most serious symptoms of Covid-19 result from an immune system on the rampage rather than a lethargic one,Chinese scientists found:An extreme immune response called cytokine storm,a flood of immune cells and the biochemicals they produce,tears through lung tissue.

　　也许免疫抑制实际上是有帮助的。中国科学家发现，covid-19最严重的一些症状是由免疫系统失控而非免疫失效引起的:一种被称为细胞因子风暴的极端免疫反应，大量的免疫细胞及其产生的生化物质撕裂肺组织。