Health officials say the disease's overall survival rate is higher in children than in adults.

卫生部表示，儿童感染新冠肺炎后的整体存活率高于成年人。

The main reason, he added, is the fact that cardiovascular disease rates have gone down in high-income countries.

他补充说，主要原因是高收入国家的心血管疾病发病率持续下降。

Mortality and disease rates vary by social class, with upper class Americans living longer and healthier lives.

死亡率和患病率因社会阶层而异，上层美国人的寿命更长、更健康。

Hotels can bring together people from states and countries where disease rates are higher, for example, and many people may not show signs of infection.

例如，酒店会成为来自疾病高发州和国家的人们的聚集地，而且很多人可能没有表现出感染迹象。

The differences we find between the two groups, like the presence of tick bites in the Lyme disease study, that might explain their different disease rates are called exposures.

我们在两组之间发现的差异，比如莱姆病研究中蜱叮咬的存在，可能解释了他们不同的发病率，这种差异被称为“暴露”。