translation.en: And then, in one of the most important, tenacious and toughest reservoirs of the polio virus in the world, we found that our vaccine was working half as well as it should have.
translation.zh: 然后 在最重要，最顽固的 脊髓灰质炎病毒感染区 我们发现我们的疫苗 效力减半