What do R0 values mean?

R0值指什么？

Three possibilities exist for the potential transmission or decline of a disease, depending on its R0 value.

一种疾病的潜在传播或衰退存在三种可能性，这取决于它的R0值。

·If R0 is less than 1, each existing infection causes less than one new infection. In this case, the disease will decline and eventually die out.

如果R0小于1，每个现存的感染引起的新感染不会超过一次。在这种情况下，该疾病会衰退，并最终消失。

·If R0 equals 1, each existing infection causes one new infection. The disease will stay alive and stable, but there won’t be an outbreak or an epidemic.

如果R0等于1，每个现存的感染就会引发一次新的感染。该疾病会存活并稳定，但不会爆发或流行。

·If R0 is more than 1, each existing infection causes more than one new infection. The disease will be transmitted between people, and there may be an outbreak or epidemic.

   如果R0 大于1，每个现存的感染会引起不止一次的新感染。该疾病就会在人群中传播，并可能爆发并流行。

Importantly, a disease’s R0 value only applies when everyone in a population is completely vulnerable to the disease. This mean:

重要的是，一种疾病的R0值只适用于人口中完全易受该疾病攻击的人。这意味着：

   ·No one has been vaccinated

     无人接种疫苗

   ·No one has had the disease before

     之前无人得过该疾病

   ·There’s no way to control the spread of the disease

     无法控制该疾病的传播

                                      2022年12月24日译