I remember seeing something posted on NT but I couldn't find it. Hopefully someone will remember and post the info. In the meantime I looked at Pub Med and found some interesting studies. I'm not trying to worry you but here's one that may. Peripheral neuropathy after multiple tetanus toxoid injections. - PubMed - NCBI i=2&from=/18688160/related

I don't know what type of job you have and the risk you have of getting tetanus. I guess if it was me I'd do some more research and try to make an educated decision.