Can herbal supplements prevent tetanus infection?

No: Try herbals if you will, but get your shots. Trying herbs may give you comfort while you progress into a terrible death or permanant disability. They didn't help steve mcqueen with colon cancer, or steve jobs with his surgicaly curable form of pancreatic cancer. Many of our meds are derived from plants & a prudent person goes toward the best treatments from whatever source they came.

Doubtful: Some may improve you immunity, but if you become infected with clostidium tetani, the end result would not be desirable. Get the shot.

No: Forgive my frankness. If you need protection from tetanus but refuse immunization, you will very likely pay for this foolishness with your life. More generally, if you or someone you know is impressed with "herbal supplements" as equal or superior to what science offers today, go to an old graveyard and see how long people used to live. Plenty are there from tetanus.