题目选项分析

Which of the following most logically completes the argument?

A new drug, taken twice daily for one month, is an effective treatment for a certain disease. The drug now most commonly prescribed for the disease occasionally has serious side effects such as seizures; in field tests, the new drug's side effects, though no worse than mild nausea, turned out to be much more frequent. Nevertheless, the new drug is clearly preferable as a treatment, since _____.

【选项】people who have received effective treatment for disease do not generally contract the disease again