Colds mutate even while they're infecting you, and new strains pop up so often that by the time drug-makers create a vaccine against one variation, the serum is already out of date.

即使在感染你的时候，感冒病毒也会发生变异，而且新的病毒毒株经常出现，以至于当制药商研制出针对其中一种变异的疫苗时，血清已经过时了。

youdao

Serum drug concentration, were determined by HPLC.

用HPLC法测定血清药物浓度。

youdao

Supplement of potassium, calcium and protein could postpone the influence of drug on serum calcium and protein but could not reduce the incidence rates.

用药过程中补充钾、钙、蛋白质等，可推迟药物对血钾、血钙、血清蛋白的不良影响，但并不能降低发生率。

youdao

When a liver-transplant patient urgently needed immune globulin serum, customer reps drove six hours to get the drug from Paducah, Ky. to the hospital.

FORBES: Easy Pill to Swallow