When I was a kid, my Mom almost gave me Tetanus with all the Tetanus shots she got me. That is what our final for life doctor told her. We finally found a good doctor and kept him for the next 40 years, a REALLY good doctor, who became like a family member for the rest of my life. I never forget, he told my mother that Tetanus does not survive in water. All of the cuts that Mom gave me T shots for were from rusty saltwater piers and such. I spent my youth in the saltwater fishing with rod, spear, net, and all other water activities.
People have been getting Tetanus shots for at least 60+ years, very common shot. I have not heard of any problems with the shot other than getting too many and for the wrong reasons (like my Mom did).