But there were problems with Jenner's method,

詹纳的方法也有问题
and it was to require a series of subsequent improvements to

这方法还需要进行一系列的后续改进
make vaccination a fully successful procedure.

才能成为完善的疫苗接种方法
The problems involved such things as he required,

问题之一是詹纳那时
at the time, an arm-to-arm method,

需要一种肩对肩的接种方法
and this entailed the risk of spreading other diseases,

这就在预防天花的同时给了其他疾病
in particular syphilis, while trying to present smallpox.

传播的机会尤其是梅毒
There were also failed vaccinations that led to complications,

也有不成功而引起并发症的接种案例
and Jenner made a crucial mistake.

而且詹纳犯了一个严重的错误
He made it an article of dogmatic faith that the immunity

他像信奉教条那样相信人工天花接种
derived from smallpox vaccination artificially was

带来的抵抗力已经是终身保留的了
life-long, just like the natural immunity

就像自然生病活得的天花免疫力那样