And finally, British scientists have found a man with an immune system disorder has been unwittingly spreading polio for nearly 30 years despite having been vaccinated against the disease.

最后，英国科学家发现，一名患有免疫系统疾病的男子在不知情的情况下携带小儿麻痹症病毒将近30年的时间，尽管他注射过疫苗。